creation_sourcecode: // SPDX-License-Identifier: MIT
  
  // File: src/contract/openzeppelin-contracts/contracts/utils/introspection/IERC165.sol
  
  // OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @dev Interface of the ERC165 standard, as defined in the
   * https://eips.ethereum.org/EIPS/eip-165[EIP].
   *
   * Implementers can declare support of contract interfaces, which can then be
   * queried by others ({ERC165Checker}).
   *
   * For an implementation, see {ERC165}.
   */
  interface IERC165 {
      /**
       * @dev Returns true if this contract implements the interface defined by
       * `interfaceId`. See the corresponding
       * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
       * to learn more about how these ids are created.
       *
       * This function call must use less than 30 000 gas.
       */
      function supportsInterface(bytes4 interfaceId) external view returns (bool);
  }
  
  // File: src/contract/openzeppelin-contracts/contracts/token/ERC721/IERC721.sol
  
  // OpenZeppelin Contracts (last updated v4.8.0-rc.2) (token/ERC721/IERC721.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @dev Required interface of an ERC721 compliant contract.
   */
  interface IERC721 is IERC165 {
      /**
       * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
       */
      event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
  
      /**
       * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
       */
      event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
  
      /**
       * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
       */
      event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
  
      /**
       * @dev Returns the number of tokens in ``owner``'s account.
       */
      function balanceOf(address owner) external view returns (uint256 balance);
  
      /**
       * @dev Returns the owner of the `tokenId` token.
       *
       * Requirements:
       *
       * - `tokenId` must exist.
       */
      function ownerOf(uint256 tokenId) external view returns (address owner);
  
      /**
       * @dev Safely transfers `tokenId` token from `from` to `to`.
       *
       * Requirements:
       *
       * - `from` cannot be the zero address.
       * - `to` cannot be the zero address.
       * - `tokenId` token must exist and be owned by `from`.
       * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
       * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
       *
       * Emits a {Transfer} event.
       */
      function safeTransferFrom(
          address from,
          address to,
          uint256 tokenId,
          bytes calldata data
      ) external;
  
      /**
       * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
       * are aware of the ERC721 protocol to prevent tokens from being forever locked.
       *
       * Requirements:
       *
       * - `from` cannot be the zero address.
       * - `to` cannot be the zero address.
       * - `tokenId` token must exist and be owned by `from`.
       * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or {setApprovalForAll}.
       * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
       *
       * Emits a {Transfer} event.
       */
      function safeTransferFrom(
          address from,
          address to,
          uint256 tokenId
      ) external;
  
      /**
       * @dev Transfers `tokenId` token from `from` to `to`.
       *
       * WARNING: Note that the caller is responsible to confirm that the recipient is capable of receiving ERC721
       * or else they may be permanently lost. Usage of {safeTransferFrom} prevents loss, though the caller must
       * understand this adds an external call which potentially creates a reentrancy vulnerability.
       *
       * Requirements:
       *
       * - `from` cannot be the zero address.
       * - `to` cannot be the zero address.
       * - `tokenId` token must be owned by `from`.
       * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
       *
       * Emits a {Transfer} event.
       */
      function transferFrom(
          address from,
          address to,
          uint256 tokenId
      ) external;
  
      /**
       * @dev Gives permission to `to` to transfer `tokenId` token to another account.
       * The approval is cleared when the token is transferred.
       *
       * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
       *
       * Requirements:
       *
       * - The caller must own the token or be an approved operator.
       * - `tokenId` must exist.
       *
       * Emits an {Approval} event.
       */
      function approve(address to, uint256 tokenId) external;
  
      /**
       * @dev Approve or remove `operator` as an operator for the caller.
       * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
       *
       * Requirements:
       *
       * - The `operator` cannot be the caller.
       *
       * Emits an {ApprovalForAll} event.
       */
      function setApprovalForAll(address operator, bool _approved) external;
  
      /**
       * @dev Returns the account approved for `tokenId` token.
       *
       * Requirements:
       *
       * - `tokenId` must exist.
       */
      function getApproved(uint256 tokenId) external view returns (address operator);
  
      /**
       * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
       *
       * See {setApprovalForAll}
       */
      function isApprovedForAll(address owner, address operator) external view returns (bool);
  }
  
  // File: src/contract/openzeppelin-contracts/contracts/token/ERC721/IERC721Receiver.sol
  
  // OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @title ERC721 token receiver interface
   * @dev Interface for any contract that wants to support safeTransfers
   * from ERC721 asset contracts.
   */
  interface IERC721Receiver {
      /**
       * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
       * by `operator` from `from`, this function is called.
       *
       * It must return its Solidity selector to confirm the token transfer.
       * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
       *
       * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.
       */
      function onERC721Received(
          address operator,
          address from,
          uint256 tokenId,
          bytes calldata data
      ) external returns (bytes4);
  }
  
  // File: src/contract/openzeppelin-contracts/contracts/token/ERC721/extensions/IERC721Metadata.sol
  
  // OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
   * @dev See https://eips.ethereum.org/EIPS/eip-721
   */
  interface IERC721Metadata is IERC721 {
      /**
       * @dev Returns the token collection name.
       */
      function name() external view returns (string memory);
  
      /**
       * @dev Returns the token collection symbol.
       */
      function symbol() external view returns (string memory);
  
      /**
       * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
       */
      function tokenURI(uint256 tokenId) external view returns (string memory);
  }
  
  // File: src/contract/openzeppelin-contracts/contracts/utils/Address.sol
  
  // OpenZeppelin Contracts (last updated v4.8.0-rc.2) (utils/Address.sol)
  
  pragma solidity ^0.8.1;
  
  /**
   * @dev Collection of functions related to the address type
   */
  library Address {
      /**
       * @dev Returns true if `account` is a contract.
       *
       * [IMPORTANT]
       * ====
       * It is unsafe to assume that an address for which this function returns
       * false is an externally-owned account (EOA) and not a contract.
       *
       * Among others, `isContract` will return false for the following
       * types of addresses:
       *
       *  - an externally-owned account
       *  - a contract in construction
       *  - an address where a contract will be created
       *  - an address where a contract lived, but was destroyed
       * ====
       *
       * [IMPORTANT]
       * ====
       * You shouldn't rely on `isContract` to protect against flash loan attacks!
       *
       * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
       * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
       * constructor.
       * ====
       */
      function isContract(address account) internal view returns (bool) {
          // This method relies on extcodesize/address.code.length, which returns 0
          // for contracts in construction, since the code is only stored at the end
          // of the constructor execution.
  
          return account.code.length > 0;
      }
  
      /**
       * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
       * `recipient`, forwarding all available gas and reverting on errors.
       *
       * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
       * of certain opcodes, possibly making contracts go over the 2300 gas limit
       * imposed by `transfer`, making them unable to receive funds via
       * `transfer`. {sendValue} removes this limitation.
       *
       * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
       *
       * IMPORTANT: because control is transferred to `recipient`, care must be
       * taken to not create reentrancy vulnerabilities. Consider using
       * {ReentrancyGuard} or the
       * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
       */
      function sendValue(address payable recipient, uint256 amount) internal {
          require(address(this).balance >= amount, "Address: insufficient balance");
  
          (bool success, ) = recipient.call{value: amount}("");
          require(success, "Address: unable to send value, recipient may have reverted");
      }
  
      /**
       * @dev Performs a Solidity function call using a low level `call`. A
       * plain `call` is an unsafe replacement for a function call: use this
       * function instead.
       *
       * If `target` reverts with a revert reason, it is bubbled up by this
       * function (like regular Solidity function calls).
       *
       * Returns the raw returned data. To convert to the expected return value,
       * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
       *
       * Requirements:
       *
       * - `target` must be a contract.
       * - calling `target` with `data` must not revert.
       *
       * _Available since v3.1._
       */
      function functionCall(address target, bytes memory data) internal returns (bytes memory) {
          return functionCallWithValue(target, data, 0, "Address: low-level call failed");
      }
  
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
       * `errorMessage` as a fallback revert reason when `target` reverts.
       *
       * _Available since v3.1._
       */
      function functionCall(
          address target,
          bytes memory data,
          string memory errorMessage
      ) internal returns (bytes memory) {
          return functionCallWithValue(target, data, 0, errorMessage);
      }
  
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
       * but also transferring `value` wei to `target`.
       *
       * Requirements:
       *
       * - the calling contract must have an ETH balance of at least `value`.
       * - the called Solidity function must be `payable`.
       *
       * _Available since v3.1._
       */
      function functionCallWithValue(
          address target,
          bytes memory data,
          uint256 value
      ) internal returns (bytes memory) {
          return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
      }
  
      /**
       * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
       * with `errorMessage` as a fallback revert reason when `target` reverts.
       *
       * _Available since v3.1._
       */
      function functionCallWithValue(
          address target,
          bytes memory data,
          uint256 value,
          string memory errorMessage
      ) internal returns (bytes memory) {
          require(address(this).balance >= value, "Address: insufficient balance for call");
          (bool success, bytes memory returndata) = target.call{value: value}(data);
          return verifyCallResultFromTarget(target, success, returndata, errorMessage);
      }
  
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
       * but performing a static call.
       *
       * _Available since v3.3._
       */
      function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
          return functionStaticCall(target, data, "Address: low-level static call failed");
      }
  
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
       * but performing a static call.
       *
       * _Available since v3.3._
       */
      function functionStaticCall(
          address target,
          bytes memory data,
          string memory errorMessage
      ) internal view returns (bytes memory) {
          (bool success, bytes memory returndata) = target.staticcall(data);
          return verifyCallResultFromTarget(target, success, returndata, errorMessage);
      }
  
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
       * but performing a delegate call.
       *
       * _Available since v3.4._
       */
      function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
          return functionDelegateCall(target, data, "Address: low-level delegate call failed");
      }
  
      /**
       * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
       * but performing a delegate call.
       *
       * _Available since v3.4._
       */
      function functionDelegateCall(
          address target,
          bytes memory data,
          string memory errorMessage
      ) internal returns (bytes memory) {
          (bool success, bytes memory returndata) = target.delegatecall(data);
          return verifyCallResultFromTarget(target, success, returndata, errorMessage);
      }
  
      /**
       * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
       * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
       *
       * _Available since v4.8._
       */
      function verifyCallResultFromTarget(
          address target,
          bool success,
          bytes memory returndata,
          string memory errorMessage
      ) internal view returns (bytes memory) {
          if (success) {
              if (returndata.length == 0) {
                  // only check isContract if the call was successful and the return data is empty
                  // otherwise we already know that it was a contract
                  require(isContract(target), "Address: call to non-contract");
              }
              return returndata;
          } else {
              _revert(returndata, errorMessage);
          }
      }
  
      /**
       * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
       * revert reason or using the provided one.
       *
       * _Available since v4.3._
       */
      function verifyCallResult(
          bool success,
          bytes memory returndata,
          string memory errorMessage
      ) internal pure returns (bytes memory) {
          if (success) {
              return returndata;
          } else {
              _revert(returndata, errorMessage);
          }
      }
  
      function _revert(bytes memory returndata, string memory errorMessage) private pure {
          // Look for revert reason and bubble it up if present
          if (returndata.length > 0) {
              // The easiest way to bubble the revert reason is using memory via assembly
              /// @solidity memory-safe-assembly
              assembly {
                  let returndata_size := mload(returndata)
                  revert(add(32, returndata), returndata_size)
              }
          } else {
              revert(errorMessage);
          }
      }
  }
  
  // File: src/contract/openzeppelin-contracts/contracts/utils/Context.sol
  
  // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @dev Provides information about the current execution context, including the
   * sender of the transaction and its data. While these are generally available
   * via msg.sender and msg.data, they should not be accessed in such a direct
   * manner, since when dealing with meta-transactions the account sending and
   * paying for execution may not be the actual sender (as far as an application
   * is concerned).
   *
   * This contract is only required for intermediate, library-like contracts.
   */
  abstract contract Context {
      function _msgSender() internal view virtual returns (address) {
          return msg.sender;
      }
  
      function _msgData() internal view virtual returns (bytes calldata) {
          return msg.data;
      }
  }
  
  // File: src/contract/openzeppelin-contracts/contracts/utils/math/Math.sol
  
  // OpenZeppelin Contracts (last updated v4.8.0-rc.2) (utils/math/Math.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @dev Standard math utilities missing in the Solidity language.
   */
  library Math {
      enum Rounding {
          Down, // Toward negative infinity
          Up, // Toward infinity
          Zero // Toward zero
      }
  
      /**
       * @dev Returns the largest of two numbers.
       */
      function max(uint256 a, uint256 b) internal pure returns (uint256) {
          return a > b ? a : b;
      }
  
      /**
       * @dev Returns the smallest of two numbers.
       */
      function min(uint256 a, uint256 b) internal pure returns (uint256) {
          return a < b ? a : b;
      }
  
      /**
       * @dev Returns the average of two numbers. The result is rounded towards
       * zero.
       */
      function average(uint256 a, uint256 b) internal pure returns (uint256) {
          // (a + b) / 2 can overflow.
          return (a & b) + (a ^ b) / 2;
      }
  
      /**
       * @dev Returns the ceiling of the division of two numbers.
       *
       * This differs from standard division with `/` in that it rounds up instead
       * of rounding down.
       */
      function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
          // (a + b - 1) / b can overflow on addition, so we distribute.
          return a == 0 ? 0 : (a - 1) / b + 1;
      }
  
      /**
       * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
       * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
       * with further edits by Uniswap Labs also under MIT license.
       */
      function mulDiv(
          uint256 x,
          uint256 y,
          uint256 denominator
      ) internal pure returns (uint256 result) {
          unchecked {
              // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
              // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
              // variables such that product = prod1 * 2^256 + prod0.
              uint256 prod0; // Least significant 256 bits of the product
              uint256 prod1; // Most significant 256 bits of the product
              assembly {
                  let mm := mulmod(x, y, not(0))
                  prod0 := mul(x, y)
                  prod1 := sub(sub(mm, prod0), lt(mm, prod0))
              }
  
              // Handle non-overflow cases, 256 by 256 division.
              if (prod1 == 0) {
                  return prod0 / denominator;
              }
  
              // Make sure the result is less than 2^256. Also prevents denominator == 0.
              require(denominator > prod1);
  
              ///////////////////////////////////////////////
              // 512 by 256 division.
              ///////////////////////////////////////////////
  
              // Make division exact by subtracting the remainder from [prod1 prod0].
              uint256 remainder;
              assembly {
                  // Compute remainder using mulmod.
                  remainder := mulmod(x, y, denominator)
  
                  // Subtract 256 bit number from 512 bit number.
                  prod1 := sub(prod1, gt(remainder, prod0))
                  prod0 := sub(prod0, remainder)
              }
  
              // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
              // See https://cs.stackexchange.com/q/138556/92363.
  
              // Does not overflow because the denominator cannot be zero at this stage in the function.
              uint256 twos = denominator & (~denominator + 1);
              assembly {
                  // Divide denominator by twos.
                  denominator := div(denominator, twos)
  
                  // Divide [prod1 prod0] by twos.
                  prod0 := div(prod0, twos)
  
                  // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                  twos := add(div(sub(0, twos), twos), 1)
              }
  
              // Shift in bits from prod1 into prod0.
              prod0 |= prod1 * twos;
  
              // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
              // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
              // four bits. That is, denominator * inv = 1 mod 2^4.
              uint256 inverse = (3 * denominator) ^ 2;
  
              // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
              // in modular arithmetic, doubling the correct bits in each step.
              inverse *= 2 - denominator * inverse; // inverse mod 2^8
              inverse *= 2 - denominator * inverse; // inverse mod 2^16
              inverse *= 2 - denominator * inverse; // inverse mod 2^32
              inverse *= 2 - denominator * inverse; // inverse mod 2^64
              inverse *= 2 - denominator * inverse; // inverse mod 2^128
              inverse *= 2 - denominator * inverse; // inverse mod 2^256
  
              // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
              // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
              // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
              // is no longer required.
              result = prod0 * inverse;
              return result;
          }
      }
  
      /**
       * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
       */
      function mulDiv(
          uint256 x,
          uint256 y,
          uint256 denominator,
          Rounding rounding
      ) internal pure returns (uint256) {
          uint256 result = mulDiv(x, y, denominator);
          if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
              result += 1;
          }
          return result;
      }
  
      /**
       * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
       *
       * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
       */
      function sqrt(uint256 a) internal pure returns (uint256) {
          if (a == 0) {
              return 0;
          }
  
          // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
          //
          // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
          // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
          //
          // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
          // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
          // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
          //
          // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
          uint256 result = 1 << (log2(a) >> 1);
  
          // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
          // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
          // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
          // into the expected uint128 result.
          unchecked {
              result = (result + a / result) >> 1;
              result = (result + a / result) >> 1;
              result = (result + a / result) >> 1;
              result = (result + a / result) >> 1;
              result = (result + a / result) >> 1;
              result = (result + a / result) >> 1;
              result = (result + a / result) >> 1;
              return min(result, a / result);
          }
      }
  
      /**
       * @notice Calculates sqrt(a), following the selected rounding direction.
       */
      function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
          unchecked {
              uint256 result = sqrt(a);
              return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
          }
      }
  
      /**
       * @dev Return the log in base 2, rounded down, of a positive value.
       * Returns 0 if given 0.
       */
      function log2(uint256 value) internal pure returns (uint256) {
          uint256 result = 0;
          unchecked {
              if (value >> 128 > 0) {
                  value >>= 128;
                  result += 128;
              }
              if (value >> 64 > 0) {
                  value >>= 64;
                  result += 64;
              }
              if (value >> 32 > 0) {
                  value >>= 32;
                  result += 32;
              }
              if (value >> 16 > 0) {
                  value >>= 16;
                  result += 16;
              }
              if (value >> 8 > 0) {
                  value >>= 8;
                  result += 8;
              }
              if (value >> 4 > 0) {
                  value >>= 4;
                  result += 4;
              }
              if (value >> 2 > 0) {
                  value >>= 2;
                  result += 2;
              }
              if (value >> 1 > 0) {
                  result += 1;
              }
          }
          return result;
      }
  
      /**
       * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
       * Returns 0 if given 0.
       */
      function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
          unchecked {
              uint256 result = log2(value);
              return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
          }
      }
  
      /**
       * @dev Return the log in base 10, rounded down, of a positive value.
       * Returns 0 if given 0.
       */
      function log10(uint256 value) internal pure returns (uint256) {
          uint256 result = 0;
          unchecked {
              if (value >= 10**64) {
                  value /= 10**64;
                  result += 64;
              }
              if (value >= 10**32) {
                  value /= 10**32;
                  result += 32;
              }
              if (value >= 10**16) {
                  value /= 10**16;
                  result += 16;
              }
              if (value >= 10**8) {
                  value /= 10**8;
                  result += 8;
              }
              if (value >= 10**4) {
                  value /= 10**4;
                  result += 4;
              }
              if (value >= 10**2) {
                  value /= 10**2;
                  result += 2;
              }
              if (value >= 10**1) {
                  result += 1;
              }
          }
          return result;
      }
  
      /**
       * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
       * Returns 0 if given 0.
       */
      function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
          unchecked {
              uint256 result = log10(value);
              return result + (rounding == Rounding.Up && 10**result < value ? 1 : 0);
          }
      }
  
      /**
       * @dev Return the log in base 256, rounded down, of a positive value.
       * Returns 0 if given 0.
       *
       * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
       */
      function log256(uint256 value) internal pure returns (uint256) {
          uint256 result = 0;
          unchecked {
              if (value >> 128 > 0) {
                  value >>= 128;
                  result += 16;
              }
              if (value >> 64 > 0) {
                  value >>= 64;
                  result += 8;
              }
              if (value >> 32 > 0) {
                  value >>= 32;
                  result += 4;
              }
              if (value >> 16 > 0) {
                  value >>= 16;
                  result += 2;
              }
              if (value >> 8 > 0) {
                  result += 1;
              }
          }
          return result;
      }
  
      /**
       * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
       * Returns 0 if given 0.
       */
      function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
          unchecked {
              uint256 result = log256(value);
              return result + (rounding == Rounding.Up && 1 << (result * 8) < value ? 1 : 0);
          }
      }
  }
  
  // File: src/contract/openzeppelin-contracts/contracts/utils/Strings.sol
  
  // OpenZeppelin Contracts (last updated v4.8.0-rc.2) (utils/Strings.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @dev String operations.
   */
  library Strings {
      bytes16 private constant _SYMBOLS = "0123456789abcdef";
      uint8 private constant _ADDRESS_LENGTH = 20;
  
      /**
       * @dev Converts a `uint256` to its ASCII `string` decimal representation.
       */
      function toString(uint256 value) internal pure returns (string memory) {
          unchecked {
              uint256 length = Math.log10(value) + 1;
              string memory buffer = new string(length);
              uint256 ptr;
              /// @solidity memory-safe-assembly
              assembly {
                  ptr := add(buffer, add(32, length))
              }
              while (true) {
                  ptr--;
                  /// @solidity memory-safe-assembly
                  assembly {
                      mstore8(ptr, byte(mod(value, 10), _SYMBOLS))
                  }
                  value /= 10;
                  if (value == 0) break;
              }
              return buffer;
          }
      }
  
      /**
       * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
       */
      function toHexString(uint256 value) internal pure returns (string memory) {
          unchecked {
              return toHexString(value, Math.log256(value) + 1);
          }
      }
  
      /**
       * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
       */
      function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
          bytes memory buffer = new bytes(2 * length + 2);
          buffer[0] = "0";
          buffer[1] = "x";
          for (uint256 i = 2 * length + 1; i > 1; --i) {
              buffer[i] = _SYMBOLS[value & 0xf];
              value >>= 4;
          }
          require(value == 0, "Strings: hex length insufficient");
          return string(buffer);
      }
  
      /**
       * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
       */
      function toHexString(address addr) internal pure returns (string memory) {
          return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
      }
  }
  
  // File: src/contract/openzeppelin-contracts/contracts/utils/introspection/ERC165.sol
  
  // OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @dev Implementation of the {IERC165} interface.
   *
   * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
   * for the additional interface id that will be supported. For example:
   *
   * ```solidity
   * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
   *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
   * }
   * ```
   *
   * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
   */
  abstract contract ERC165 is IERC165 {
      /**
       * @dev See {IERC165-supportsInterface}.
       */
      function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
          return interfaceId == type(IERC165).interfaceId;
      }
  }
  
  // File: src/contract/openzeppelin-contracts/contracts/token/ERC721/ERC721.sol
  
  // OpenZeppelin Contracts (last updated v4.8.0-rc.2) (token/ERC721/ERC721.sol)
  
  pragma solidity ^0.8.0;
  
  
  
  
  
  
  
  /**
   * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
   * the Metadata extension, but not including the Enumerable extension, which is available separately as
   * {ERC721Enumerable}.
   */
  contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
      using Address for address;
      using Strings for uint256;
  
      // Token name
      string private _name;
  
      // Token symbol
      string private _symbol;
  
      // Mapping from token ID to owner address
      mapping(uint256 => address) private _owners;
  
      // Mapping owner address to token count
      mapping(address => uint256) private _balances;
  
      // Mapping from token ID to approved address
      mapping(uint256 => address) private _tokenApprovals;
  
      // Mapping from owner to operator approvals
      mapping(address => mapping(address => bool)) private _operatorApprovals;
  
      /**
       * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
       */
      constructor(string memory name_, string memory symbol_) {
          _name = name_;
          _symbol = symbol_;
      }
  
      /**
       * @dev See {IERC165-supportsInterface}.
       */
      function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
          return
              interfaceId == type(IERC721).interfaceId ||
              interfaceId == type(IERC721Metadata).interfaceId ||
              super.supportsInterface(interfaceId);
      }
  
      /**
       * @dev See {IERC721-balanceOf}.
       */
      function balanceOf(address owner) public view virtual override returns (uint256) {
          require(owner != address(0), "ERC721: address zero is not a valid owner");
          return _balances[owner];
      }
  
      /**
       * @dev See {IERC721-ownerOf}.
       */
      function ownerOf(uint256 tokenId) public view virtual override returns (address) {
          address owner = _ownerOf(tokenId);
          require(owner != address(0), "ERC721: invalid token ID");
          return owner;
      }
  
      /**
       * @dev See {IERC721Metadata-name}.
       */
      function name() public view virtual override returns (string memory) {
          return _name;
      }
  
      /**
       * @dev See {IERC721Metadata-symbol}.
       */
      function symbol() public view virtual override returns (string memory) {
          return _symbol;
      }
  
      /**
       * @dev See {IERC721Metadata-tokenURI}.
       */
      function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
          _requireMinted(tokenId);
  
          string memory baseURI = _baseURI();
          return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
      }
  
      /**
       * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
       * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
       * by default, can be overridden in child contracts.
       */
      function _baseURI() internal view virtual returns (string memory) {
          return "";
      }
  
      /**
       * @dev See {IERC721-approve}.
       */
      function approve(address to, uint256 tokenId) public virtual override {
          address owner = ERC721.ownerOf(tokenId);
          require(to != owner, "ERC721: approval to current owner");
  
          require(
              _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
              "ERC721: approve caller is not token owner or approved for all"
          );
  
          _approve(to, tokenId);
      }
  
      /**
       * @dev See {IERC721-getApproved}.
       */
      function getApproved(uint256 tokenId) public view virtual override returns (address) {
          _requireMinted(tokenId);
  
          return _tokenApprovals[tokenId];
      }
  
      /**
       * @dev See {IERC721-setApprovalForAll}.
       */
      function setApprovalForAll(address operator, bool approved) public virtual override {
          _setApprovalForAll(_msgSender(), operator, approved);
      }
  
      /**
       * @dev See {IERC721-isApprovedForAll}.
       */
      function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
          return _operatorApprovals[owner][operator];
      }
  
      /**
       * @dev See {IERC721-transferFrom}.
       */
      function transferFrom(
          address from,
          address to,
          uint256 tokenId
      ) public virtual override {
          //solhint-disable-next-line max-line-length
          require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner or approved");
  
          _transfer(from, to, tokenId);
      }
  
      /**
       * @dev See {IERC721-safeTransferFrom}.
       */
      function safeTransferFrom(
          address from,
          address to,
          uint256 tokenId
      ) public virtual override {
          safeTransferFrom(from, to, tokenId, "");
      }
  
      /**
       * @dev See {IERC721-safeTransferFrom}.
       */
      function safeTransferFrom(
          address from,
          address to,
          uint256 tokenId,
          bytes memory data
      ) public virtual override {
          require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner or approved");
          _safeTransfer(from, to, tokenId, data);
      }
  
      /**
       * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
       * are aware of the ERC721 protocol to prevent tokens from being forever locked.
       *
       * `data` is additional data, it has no specified format and it is sent in call to `to`.
       *
       * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
       * implement alternative mechanisms to perform token transfer, such as signature-based.
       *
       * Requirements:
       *
       * - `from` cannot be the zero address.
       * - `to` cannot be the zero address.
       * - `tokenId` token must exist and be owned by `from`.
       * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
       *
       * Emits a {Transfer} event.
       */
      function _safeTransfer(
          address from,
          address to,
          uint256 tokenId,
          bytes memory data
      ) internal virtual {
          _transfer(from, to, tokenId);
          require(_checkOnERC721Received(from, to, tokenId, data), "ERC721: transfer to non ERC721Receiver implementer");
      }
  
      /**
       * @dev Returns the owner of the `tokenId`. Does NOT revert if token doesn't exist
       */
      function _ownerOf(uint256 tokenId) internal view virtual returns (address) {
          return _owners[tokenId];
      }
  
      /**
       * @dev Returns whether `tokenId` exists.
       *
       * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
       *
       * Tokens start existing when they are minted (`_mint`),
       * and stop existing when they are burned (`_burn`).
       */
      function _exists(uint256 tokenId) internal view virtual returns (bool) {
          return _ownerOf(tokenId) != address(0);
      }
  
      /**
       * @dev Returns whether `spender` is allowed to manage `tokenId`.
       *
       * Requirements:
       *
       * - `tokenId` must exist.
       */
      function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
          address owner = ERC721.ownerOf(tokenId);
          return (spender == owner || isApprovedForAll(owner, spender) || getApproved(tokenId) == spender);
      }
  
      /**
       * @dev Safely mints `tokenId` and transfers it to `to`.
       *
       * Requirements:
       *
       * - `tokenId` must not exist.
       * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
       *
       * Emits a {Transfer} event.
       */
      function _safeMint(address to, uint256 tokenId) internal virtual {
          _safeMint(to, tokenId, "");
      }
  
      /**
       * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
       * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
       */
      function _safeMint(
          address to,
          uint256 tokenId,
          bytes memory data
      ) internal virtual {
          _mint(to, tokenId);
          require(
              _checkOnERC721Received(address(0), to, tokenId, data),
              "ERC721: transfer to non ERC721Receiver implementer"
          );
      }
  
      /**
       * @dev Mints `tokenId` and transfers it to `to`.
       *
       * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
       *
       * Requirements:
       *
       * - `tokenId` must not exist.
       * - `to` cannot be the zero address.
       *
       * Emits a {Transfer} event.
       */
      function _mint(address to, uint256 tokenId) internal virtual {
          require(to != address(0), "ERC721: mint to the zero address");
          require(!_exists(tokenId), "ERC721: token already minted");
  
          _beforeTokenTransfer(address(0), to, tokenId, 1);
  
          // Check that tokenId was not minted by `_beforeTokenTransfer` hook
          require(!_exists(tokenId), "ERC721: token already minted");
  
          unchecked {
              // Will not overflow unless all 2**256 token ids are minted to the same owner.
              // Given that tokens are minted one by one, it is impossible in practice that
              // this ever happens. Might change if we allow batch minting.
              // The ERC fails to describe this case.
              _balances[to] += 1;
          }
  
          _owners[tokenId] = to;
  
          emit Transfer(address(0), to, tokenId);
  
          _afterTokenTransfer(address(0), to, tokenId, 1);
      }
  
      /**
       * @dev Destroys `tokenId`.
       * The approval is cleared when the token is burned.
       * This is an internal function that does not check if the sender is authorized to operate on the token.
       *
       * Requirements:
       *
       * - `tokenId` must exist.
       *
       * Emits a {Transfer} event.
       */
      function _burn(uint256 tokenId) internal virtual {
          address owner = ERC721.ownerOf(tokenId);
  
          _beforeTokenTransfer(owner, address(0), tokenId, 1);
  
          // Update ownership in case tokenId was transferred by `_beforeTokenTransfer` hook
          owner = ERC721.ownerOf(tokenId);
  
          // Clear approvals
          delete _tokenApprovals[tokenId];
  
          unchecked {
              // Cannot overflow, as that would require more tokens to be burned/transferred
              // out than the owner initially received through minting and transferring in.
              _balances[owner] -= 1;
          }
          delete _owners[tokenId];
  
          emit Transfer(owner, address(0), tokenId);
  
          _afterTokenTransfer(owner, address(0), tokenId, 1);
      }
  
      /**
       * @dev Transfers `tokenId` from `from` to `to`.
       *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
       *
       * Requirements:
       *
       * - `to` cannot be the zero address.
       * - `tokenId` token must be owned by `from`.
       *
       * Emits a {Transfer} event.
       */
      function _transfer(
          address from,
          address to,
          uint256 tokenId
      ) internal virtual {
          require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer from incorrect owner");
          require(to != address(0), "ERC721: transfer to the zero address");
  
          _beforeTokenTransfer(from, to, tokenId, 1);
  
          // Check that tokenId was not transferred by `_beforeTokenTransfer` hook
          require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer from incorrect owner");
  
          // Clear approvals from the previous owner
          delete _tokenApprovals[tokenId];
  
          unchecked {
              // `_balances[from]` cannot overflow for the same reason as described in `_burn`:
              // `from`'s balance is the number of token held, which is at least one before the current
              // transfer.
              // `_balances[to]` could overflow in the conditions described in `_mint`. That would require
              // all 2**256 token ids to be minted, which in practice is impossible.
              _balances[from] -= 1;
              _balances[to] += 1;
          }
          _owners[tokenId] = to;
  
          emit Transfer(from, to, tokenId);
  
          _afterTokenTransfer(from, to, tokenId, 1);
      }
  
      /**
       * @dev Approve `to` to operate on `tokenId`
       *
       * Emits an {Approval} event.
       */
      function _approve(address to, uint256 tokenId) internal virtual {
          _tokenApprovals[tokenId] = to;
          emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
      }
  
      /**
       * @dev Approve `operator` to operate on all of `owner` tokens
       *
       * Emits an {ApprovalForAll} event.
       */
      function _setApprovalForAll(
          address owner,
          address operator,
          bool approved
      ) internal virtual {
          require(owner != operator, "ERC721: approve to caller");
          _operatorApprovals[owner][operator] = approved;
          emit ApprovalForAll(owner, operator, approved);
      }
  
      /**
       * @dev Reverts if the `tokenId` has not been minted yet.
       */
      function _requireMinted(uint256 tokenId) internal view virtual {
          require(_exists(tokenId), "ERC721: invalid token ID");
      }
  
      /**
       * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
       * The call is not executed if the target address is not a contract.
       *
       * @param from address representing the previous owner of the given token ID
       * @param to target address that will receive the tokens
       * @param tokenId uint256 ID of the token to be transferred
       * @param data bytes optional data to send along with the call
       * @return bool whether the call correctly returned the expected magic value
       */
      function _checkOnERC721Received(
          address from,
          address to,
          uint256 tokenId,
          bytes memory data
      ) private returns (bool) {
          if (to.isContract()) {
              try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, data) returns (bytes4 retval) {
                  return retval == IERC721Receiver.onERC721Received.selector;
              } catch (bytes memory reason) {
                  if (reason.length == 0) {
                      revert("ERC721: transfer to non ERC721Receiver implementer");
                  } else {
                      /// @solidity memory-safe-assembly
                      assembly {
                          revert(add(32, reason), mload(reason))
                      }
                  }
              }
          } else {
              return true;
          }
      }
  
      /**
       * @dev Hook that is called before any token transfer. This includes minting and burning. If {ERC721Consecutive} is
       * used, the hook may be called as part of a consecutive (batch) mint, as indicated by `batchSize` greater than 1.
       *
       * Calling conditions:
       *
       * - When `from` and `to` are both non-zero, ``from``'s tokens will be transferred to `to`.
       * - When `from` is zero, the tokens will be minted for `to`.
       * - When `to` is zero, ``from``'s tokens will be burned.
       * - `from` and `to` are never both zero.
       * - `batchSize` is non-zero.
       *
       * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
       */
      function _beforeTokenTransfer(
          address from,
          address to,
          uint256, /* firstTokenId */
          uint256 batchSize
      ) internal virtual {
          if (batchSize > 1) {
              if (from != address(0)) {
                  _balances[from] -= batchSize;
              }
              if (to != address(0)) {
                  _balances[to] += batchSize;
              }
          }
      }
  
      /**
       * @dev Hook that is called after any token transfer. This includes minting and burning. If {ERC721Consecutive} is
       * used, the hook may be called as part of a consecutive (batch) mint, as indicated by `batchSize` greater than 1.
       *
       * Calling conditions:
       *
       * - When `from` and `to` are both non-zero, ``from``'s tokens were transferred to `to`.
       * - When `from` is zero, the tokens were minted for `to`.
       * - When `to` is zero, ``from``'s tokens were burned.
       * - `from` and `to` are never both zero.
       * - `batchSize` is non-zero.
       *
       * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
       */
      function _afterTokenTransfer(
          address from,
          address to,
          uint256 firstTokenId,
          uint256 batchSize
      ) internal virtual {}
  }
  
  // File: src/contract/openzeppelin-contracts/contracts/access/Ownable.sol
  
  // OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @dev Contract module which provides a basic access control mechanism, where
   * there is an account (an owner) that can be granted exclusive access to
   * specific functions.
   *
   * By default, the owner account will be the one that deploys the contract. This
   * can later be changed with {transferOwnership}.
   *
   * This module is used through inheritance. It will make available the modifier
   * `onlyOwner`, which can be applied to your functions to restrict their use to
   * the owner.
   */
  abstract contract Ownable is Context {
      address private _owner;
  
      event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
  
      /**
       * @dev Initializes the contract setting the deployer as the initial owner.
       */
      constructor() {
          _transferOwnership(_msgSender());
      }
  
      /**
       * @dev Throws if called by any account other than the owner.
       */
      modifier onlyOwner() {
          _checkOwner();
          _;
      }
  
      /**
       * @dev Returns the address of the current owner.
       */
      function owner() public view virtual returns (address) {
          return _owner;
      }
  
      /**
       * @dev Throws if the sender is not the owner.
       */
      function _checkOwner() internal view virtual {
          require(owner() == _msgSender(), "Ownable: caller is not the owner");
      }
  
      /**
       * @dev Leaves the contract without owner. It will not be possible to call
       * `onlyOwner` functions anymore. Can only be called by the current owner.
       *
       * NOTE: Renouncing ownership will leave the contract without an owner,
       * thereby removing any functionality that is only available to the owner.
       */
      function renounceOwnership() public virtual onlyOwner {
          _transferOwnership(address(0));
      }
  
      /**
       * @dev Transfers ownership of the contract to a new account (`newOwner`).
       * Can only be called by the current owner.
       */
      function transferOwnership(address newOwner) public virtual onlyOwner {
          require(newOwner != address(0), "Ownable: new owner is the zero address");
          _transferOwnership(newOwner);
      }
  
      /**
       * @dev Transfers ownership of the contract to a new account (`newOwner`).
       * Internal function without access restriction.
       */
      function _transferOwnership(address newOwner) internal virtual {
          address oldOwner = _owner;
          _owner = newOwner;
          emit OwnershipTransferred(oldOwner, newOwner);
      }
  }
  
  // File: src/contract/openzeppelin-contracts/contracts/utils/Base64.sol
  
  // OpenZeppelin Contracts (last updated v4.7.0) (utils/Base64.sol)
  
  pragma solidity ^0.8.0;
  
  /**
   * @dev Provides a set of functions to operate with Base64 strings.
   *
   * _Available since v4.5._
   */
  library Base64 {
      /**
       * @dev Base64 Encoding/Decoding Table
       */
      string internal constant _TABLE = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  
      /**
       * @dev Converts a `bytes` to its Bytes64 `string` representation.
       */
      function encode(bytes memory data) internal pure returns (string memory) {
          /**
           * Inspired by Brecht Devos (Brechtpd) implementation - MIT licence
           * https://github.com/Brechtpd/base64/blob/e78d9fd951e7b0977ddca77d92dc85183770daf4/base64.sol
           */
          if (data.length == 0) return "";
  
          // Loads the table into memory
          string memory table = _TABLE;
  
          // Encoding takes 3 bytes chunks of binary data from `bytes` data parameter
          // and split into 4 numbers of 6 bits.
          // The final Base64 length should be `bytes` data length multiplied by 4/3 rounded up
          // - `data.length + 2`  -> Round up
          // - `/ 3`              -> Number of 3-bytes chunks
          // - `4 *`              -> 4 characters for each chunk
          string memory result = new string(4 * ((data.length + 2) / 3));
  
          /// @solidity memory-safe-assembly
          assembly {
              // Prepare the lookup table (skip the first "length" byte)
              let tablePtr := add(table, 1)
  
              // Prepare result pointer, jump over length
              let resultPtr := add(result, 32)
  
              // Run over the input, 3 bytes at a time
              for {
                  let dataPtr := data
                  let endPtr := add(data, mload(data))
              } lt(dataPtr, endPtr) {
  
              } {
                  // Advance 3 bytes
                  dataPtr := add(dataPtr, 3)
                  let input := mload(dataPtr)
  
                  // To write each character, shift the 3 bytes (18 bits) chunk
                  // 4 times in blocks of 6 bits for each character (18, 12, 6, 0)
                  // and apply logical AND with 0x3F which is the number of
                  // the previous character in the ASCII table prior to the Base64 Table
                  // The result is then added to the table to get the character to write,
                  // and finally write it in the result pointer but with a left shift
                  // of 256 (1 byte) - 8 (1 ASCII char) = 248 bits
  
                  mstore8(resultPtr, mload(add(tablePtr, and(shr(18, input), 0x3F))))
                  resultPtr := add(resultPtr, 1) // Advance
  
                  mstore8(resultPtr, mload(add(tablePtr, and(shr(12, input), 0x3F))))
                  resultPtr := add(resultPtr, 1) // Advance
  
                  mstore8(resultPtr, mload(add(tablePtr, and(shr(6, input), 0x3F))))
                  resultPtr := add(resultPtr, 1) // Advance
  
                  mstore8(resultPtr, mload(add(tablePtr, and(input, 0x3F))))
                  resultPtr := add(resultPtr, 1) // Advance
              }
  
              // When data `bytes` is not exactly 3 bytes long
              // it is padded with `=` characters at the end
              switch mod(mload(data), 3)
              case 1 {
                  mstore8(sub(resultPtr, 1), 0x3d)
                  mstore8(sub(resultPtr, 2), 0x3d)
              }
              case 2 {
                  mstore8(sub(resultPtr, 1), 0x3d)
              }
          }
  
          return result;
      }
  }
  
  // File: src/contract/EARTH.sol
  
  pragma solidity ^0.8.4;
  
  
  
  
  contract EARTH is ERC721, Ownable {
      using Strings for uint256;
  
      string constant NAME = "EARTH";
      string constant SYMBOL = "EARTH";
      string constant IMAGE_BASE_URI = "ipfs://QmckZx54qkufApdV499BJSyTDZTw6bxGGtJdgRNvk8iaM7";
      uint constant NUM_TILES = 812;
      uint constant NUM_PENTAGONS = 12;
  
      event CustomDataChanged(uint256 indexed tokenId);
  
      uint256 _maxSupply;
      mapping(uint256 => bytes) _customData;
  
      constructor() ERC721(NAME, SYMBOL) {
          _maxSupply = NUM_TILES;
      }
  
      function mint(uint256 index) payable public {
          address minter = msg.sender;
          require(index < _maxSupply, "out of bounds");
          require(msg.value >= 0.08 ether, "not enough ETH (0.08)");
  
          _safeMint(minter, index);
      }
  
      /**
       * Return owner of tile or zero address if not minted.
       */
      function ownerOfOrZero(uint256 tokenId) public view returns (address) {
          if (!_exists(tokenId)) {
              return address(0);
          }
          return ownerOf(tokenId);
      }
  
      /**
       * Return an array with all tile owners. If tile is not minted, address is zero.
       */
      function owners() external view returns (address[] memory _owners) {
          _owners = new address[](_maxSupply);
          for (uint i=0; i<_owners.length; i++) {
              _owners[i] = ownerOfOrZero(i);
          }
      }
  
      /**
       * Transfer contract funds to owner.
       */
      function withdraw() public onlyOwner {
          address owner = owner();
          uint256 balance = address(this).balance;
          payable(owner).transfer(balance);
      }
  
      /**
       * Meta data
       */
  
      /**
       * @dev See {IERC721Metadata-tokenURI}.
       */
      function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
          bytes memory dataURI = abi.encodePacked(
              '{',
                  '"name": "Tile #', tokenId.toString(), '",',
                  '"image": "', IMAGE_BASE_URI, "/tile", tokenId.toString(), '.jpeg",',
                  '"attributes": ', '[',
                      '{',
                          '"trait_type": "Shape",',
                          '"value": "', _shape(tokenId), '"',
                      '},',
                      '{',
                          '"trait_type": "Message",',
                          '"value": "', customData(tokenId), '"',
                      '}',
                  ']',
              '}'
          );
          return string(
              abi.encodePacked(
                  "data:application/json;base64,",
                  Base64.encode(dataURI)
              )
          );
      }
  
      function _shape(uint256 tokenId) internal pure returns (string memory) {
          if (tokenId < NUM_PENTAGONS) {
              return "Pentagon";
          }
          return "Hexagon";
      }
  
      /**
       * Custom data
       */
  
      function setCustomData(uint256 index, bytes calldata data) public {
          require(ownerOf(index) == msg.sender, "not owner");
          _customData[index] = data;
          emit CustomDataChanged(index);
      }
  
      function customData(uint256 index) public view returns (bytes memory) {
          return _customData[index];
      }
  
      function customDataAll() external view returns (bytes[] memory _customDataAll) {
          _customDataAll = new bytes[](_maxSupply);
          for (uint i=0; i<_customDataAll.length; i++) {
              _customDataAll[i] = customData(i);
          }
      }
  }