creation_sourcecode: {{
    "language": "Solidity",
    "sources": {
      "@openzeppelin/contracts/access/Ownable.sol": {
        "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)\n\npragma solidity ^0.8.0;\n\nimport \"../utils/Context.sol\";\n\n/**\n * @dev Contract module which provides a basic access control mechanism, where\n * there is an account (an owner) that can be granted exclusive access to\n * specific functions.\n *\n * By default, the owner account will be the one that deploys the contract. This\n * can later be changed with {transferOwnership}.\n *\n * This module is used through inheritance. It will make available the modifier\n * `onlyOwner`, which can be applied to your functions to restrict their use to\n * the owner.\n */\nabstract contract Ownable is Context {\n    address private _owner;\n\n    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);\n\n    /**\n     * @dev Initializes the contract setting the deployer as the initial owner.\n     */\n    constructor() {\n        _transferOwnership(_msgSender());\n    }\n\n    /**\n     * @dev Throws if called by any account other than the owner.\n     */\n    modifier onlyOwner() {\n        _checkOwner();\n        _;\n    }\n\n    /**\n     * @dev Returns the address of the current owner.\n     */\n    function owner() public view virtual returns (address) {\n        return _owner;\n    }\n\n    /**\n     * @dev Throws if the sender is not the owner.\n     */\n    function _checkOwner() internal view virtual {\n        require(owner() == _msgSender(), \"Ownable: caller is not the owner\");\n    }\n\n    /**\n     * @dev Leaves the contract without owner. It will not be possible to call\n     * `onlyOwner` functions. Can only be called by the current owner.\n     *\n     * NOTE: Renouncing ownership will leave the contract without an owner,\n     * thereby disabling any functionality that is only available to the owner.\n     */\n    function renounceOwnership() public virtual onlyOwner {\n        _transferOwnership(address(0));\n    }\n\n    /**\n     * @dev Transfers ownership of the contract to a new account (`newOwner`).\n     * Can only be called by the current owner.\n     */\n    function transferOwnership(address newOwner) public virtual onlyOwner {\n        require(newOwner != address(0), \"Ownable: new owner is the zero address\");\n        _transferOwnership(newOwner);\n    }\n\n    /**\n     * @dev Transfers ownership of the contract to a new account (`newOwner`).\n     * Internal function without access restriction.\n     */\n    function _transferOwnership(address newOwner) internal virtual {\n        address oldOwner = _owner;\n        _owner = newOwner;\n        emit OwnershipTransferred(oldOwner, newOwner);\n    }\n}\n"
      },
      "@openzeppelin/contracts/utils/Context.sol": {
        "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Provides information about the current execution context, including the\n * sender of the transaction and its data. While these are generally available\n * via msg.sender and msg.data, they should not be accessed in such a direct\n * manner, since when dealing with meta-transactions the account sending and\n * paying for execution may not be the actual sender (as far as an application\n * is concerned).\n *\n * This contract is only required for intermediate, library-like contracts.\n */\nabstract contract Context {\n    function _msgSender() internal view virtual returns (address) {\n        return msg.sender;\n    }\n\n    function _msgData() internal view virtual returns (bytes calldata) {\n        return msg.data;\n    }\n}\n"
      },
      "src/backend/contracts/Legit/BookOfEth.sol": {
        "content": "// SPDX-License-Identifier: MIT\r\n\r\npragma solidity ^0.8.17;\r\n\r\nimport \"@openzeppelin/contracts/access/Ownable.sol\";\r\n\r\ninterface IERC20 {\r\n    /**\r\n     * @dev Returns the amount of tokens owned by `account`.\r\n     */\r\n\r\n    /**\r\n     * @dev Emitted when the allowance of a `spender` for an `owner` is set by\r\n     * a call to {approve}. `value` is the new allowance.\r\n     */\r\n    event Approval(\r\n        address indexed owner,\r\n        address indexed spender,\r\n        uint256 value\r\n    );\r\n\r\n    function balanceOf(address account) external view returns (uint256);\r\n    /**\r\n     *\r\n     * Note that `value` may be zero.\r\n     */\r\n    event Transfer(address indexed from, address indexed to, uint256 value);\r\n\r\n    function totalSupply() external view returns (uint256);\r\n\r\n    function transferFrom(\r\n        address from,\r\n        address to,\r\n        uint256 amount\r\n    ) external returns (bool);\r\n    /**\r\n     * @dev Moves `amount` tokens from the caller's account to `to`.\r\n     *\r\n     * Returns a boolean value indicating whether the operation succeeded.\r\n     *\r\n     * Emits a {Transfer} event.\r\n     */\r\n    function transfer(address to, uint256 amount) external returns (bool);\r\n\r\n    /**\r\n     * @dev Returns the remaining number of tokens that `spender` will be\r\n     * allowed to spend on behalf of `owner` through {transferFrom}. This is\r\n     * zero by default.\r\n     *\r\n     * This value changes when {approve} or {transferFrom} are called.\r\n     */\r\n    function allowance(address owner, address spender)\r\n        external\r\n        view\r\n        returns (uint256);\r\n\r\n    /**\r\n     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.\r\n     *\r\n     * Returns a boolean value indicating whether the operation succeeded.\r\n     *\r\n     * IMPORTANT: Beware that changing an allowance with this method brings the risk\r\n     * that someone may use both the old and the new allowance by unfortunate\r\n     * transaction ordering. One possible solution to mitigate this race\r\n     * condition is to first reduce the spender's allowance to 0 and set the\r\n     * desired value afterwards:\r\n     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729\r\n     *\r\n     * Emits an {Approval} event.\r\n     */\r\n    function approve(address spender, uint256 amount) external returns (bool);\r\n\r\n    /**\r\n     * @dev Moves `amount` tokens from `from` to `to` using the\r\n     * allowance mechanism. `amount` is then deducted from the caller's\r\n     * allowance.\r\n     *\r\n     * Returns a boolean value indicating whether the operation succeeded.\r\n     *\r\n     * Emits a {Transfer} event.\r\n     */\r\n}\r\n\r\n/**\r\n * @dev Interface for the optional metadata functions from the ERC20 standard.\r\n *\r\n * _Available since v4.1._\r\n */\r\ninterface IERC20Metadata is IERC20 {\r\n    function decimals() external view returns (uint8);\r\n    function name() external view returns (string memory);\r\n\r\n    /**\r\n     * @dev Returns the symbol of the token.\r\n     */\r\n    function symbol() external view returns (string memory);\r\n    /**\r\n     * @dev Returns the decimals places of the token.\r\n     */\r\n\r\n}\r\n\r\n// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/ERC20.sol)\r\n\r\n// pragma solidity ^0.8.0;\r\n\r\n// import \"./IERC20.sol\";\r\n// import \"./extensions/IERC20Metadata.sol\";\r\n// import \"../../utils/Context.sol\";\r\n\r\n/**\r\n * @dev Implementation of the {IERC20} interface.\r\n *\r\n */\r\ncontract ERC20 is Context, IERC20, IERC20Metadata {\r\n    mapping(address => uint256) private _balances;\r\n\r\n    mapping(address => mapping(address => uint256)) private _allowances;\r\n\r\n    uint256 private _totalSupply;\r\n\r\n    string private _name;\r\n    string private _symbol;\r\n\r\n    /**\r\n     * @dev Sets the values for {name} and {symbol}.\r\n     */\r\n    constructor(string memory name_, string memory symbol_) {\r\n        _name = name_;\r\n        _symbol = symbol_;\r\n    }\r\n\r\n    function name() public view virtual override returns (string memory) {\r\n        return _name;\r\n    }\r\n\r\n    /**\r\n     * @dev See {IERC20-totalSupply}.\r\n     */\r\n    function totalSupply() public view virtual override returns (uint256) {\r\n        return _totalSupply;\r\n    }\r\n    /**\r\n     * @dev Returns the name of the token.\r\n     */\r\n\r\n    /**\r\n     * @dev Returns the symbol of the token, usually a shorter version of the\r\n     * name.\r\n     */\r\n    function symbol() public view virtual override returns (string memory) {\r\n        return _symbol;\r\n    }\r\n\r\n    /**\r\n     * @dev See {IERC20-transfer}.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `to` cannot be the zero address.\r\n     * - the caller must have a balance of at least `amount`.\r\n     */\r\n    function transfer(address to, uint256 amount)\r\n        public\r\n        virtual\r\n        override\r\n        returns (bool)\r\n    {\r\n        address owner = _msgSender();\r\n        _transfer(owner, to, amount);\r\n        return true;\r\n    }\r\n    /**\r\n     * @dev Returns the number of decimals used to get its user representation.\r\n     * For example, if `decimals` equals `2`, a balance of `505` tokens should\r\n     * be displayed to a user as `5.05` (`505 / 10 ** 2`).\r\n     *\r\n     * Tokens usually opt for a value of 18, imitating the relationship between\r\n     * Ether and Wei. This is the default value returned by this function, unless\r\n     * it's overridden.\r\n     *\r\n     * NOTE: This information is only used for _display_ purposes: it in\r\n     * no way affects any of the arithmetic of the contract, including\r\n     * {IERC20-balanceOf} and {IERC20-transfer}.\r\n     */\r\n\r\n    /**\r\n     * @dev See {IERC20-balanceOf}.\r\n     */\r\n    function balanceOf(address account)\r\n        public\r\n        view\r\n        virtual\r\n        override\r\n        returns (uint256)\r\n    {\r\n        return _balances[account];\r\n    }\r\n\r\n\r\n    /**\r\n     * @dev See {IERC20-allowance}.\r\n     */\r\n    function allowance(address owner, address spender)\r\n        public\r\n        view\r\n        virtual\r\n        override\r\n        returns (uint256)\r\n    {\r\n        return _allowances[owner][spender];\r\n    }\r\n\r\n    /**\r\n     * @dev See {IERC20-approve}.\r\n     *\r\n     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on\r\n     * `transferFrom`. This is semantically equivalent to an infinite approval.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `spender` cannot be the zero address.\r\n     */\r\n    function approve(address spender, uint256 amount)\r\n        public\r\n        virtual\r\n        override\r\n        returns (bool)\r\n    {\r\n        address owner = _msgSender();\r\n        _approve(owner, spender, amount);\r\n        return true;\r\n    }\r\n\r\n    /**\r\n     * @dev See {IERC20-transferFrom}.\r\n     *\r\n     * Emits an {Approval} event indicating the updated allowance. This is not\r\n     * required by the EIP. See the note at the beginning of {ERC20}.\r\n     *\r\n     * NOTE: Does not update the allowance if the current allowance\r\n     * is the maximum `uint256`.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `from` and `to` cannot be the zero address.\r\n     * - `from` must have a balance of at least `amount`.\r\n     * - the caller must have allowance for ``from``'s tokens of at least\r\n     * `amount`.\r\n     */\r\n    function transferFrom(\r\n        address from,\r\n        address to,\r\n        uint256 amount\r\n    ) public virtual override returns (bool) {\r\n        address spender = _msgSender();\r\n        _spendAllowance(from, spender, amount);\r\n        _transfer(from, to, amount);\r\n        return true;\r\n    }\r\n\r\n    function _mint(address account, uint256 amount) internal virtual {\r\n        require(account != address(0), \"ERC20: mint to the zero address\");\r\n\r\n        _beforeTokenTransfer(address(0), account, amount);\r\n\r\n        _totalSupply += amount;\r\n        unchecked {\r\n            // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.\r\n            _balances[account] += amount;\r\n        }\r\n        emit Transfer(address(0), account, amount);\r\n\r\n        _afterTokenTransfer(address(0), account, amount);\r\n    }\r\n    function decimals() public view virtual override returns (uint8) {\r\n        return 18;\r\n    }\r\n    function _transfer(\r\n        address from,\r\n        address to,\r\n        uint256 amount\r\n    ) internal virtual {\r\n        require(from != address(0), \"ERC20: transfer from the zero address\");\r\n        require(to != address(0), \"ERC20: transfer to the zero address\");\r\n\r\n        _beforeTokenTransfer(from, to, amount);\r\n\r\n        uint256 fromBalance = _balances[from];\r\n        require(\r\n            fromBalance >= amount,\r\n            \"ERC20: transfer amount exceeds balance\"\r\n        );\r\n        unchecked {\r\n            _balances[from] = fromBalance - amount;\r\n            // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by\r\n            // decrementing then incrementing.\r\n            _balances[to] += amount;\r\n        }\r\n\r\n        emit Transfer(from, to, amount);\r\n\r\n        _afterTokenTransfer(from, to, amount);\r\n    }\r\n\r\n    /**\r\n     * @dev Atomically increases the allowance granted to `spender` by the caller.\r\n     *\r\n     * This is an alternative to {approve} that can be used as a mitigation for\r\n     * problems described in {IERC20-approve}.\r\n     *\r\n     * Emits an {Approval} event indicating the updated allowance.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `spender` cannot be the zero address.\r\n     */\r\n    function increaseAllowance(address spender, uint256 addedValue)\r\n        public\r\n        virtual\r\n        returns (bool)\r\n    {\r\n        address owner = _msgSender();\r\n        _approve(owner, spender, allowance(owner, spender) + addedValue);\r\n        return true;\r\n    }\r\n    /** @dev Creates `amount` tokens and assigns them to `account`, increasing\r\n     * the total supply.\r\n     *\r\n     * Emits a {Transfer} event with `from` set to the zero address.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `account` cannot be the zero address.\r\n     */\r\n    /**\r\n     * @dev Atomically decreases the allowance granted to `spender` by the caller.\r\n     *\r\n     * This is an alternative to {approve} that can be used as a mitigation for\r\n     * problems described in {IERC20-approve}.\r\n     *\r\n     * Emits an {Approval} event indicating the updated allowance.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `spender` cannot be the zero address.\r\n     * - `spender` must have allowance for the caller of at least\r\n     * `subtractedValue`.\r\n     */\r\n    /**\r\n     * @dev Moves `amount` of tokens from `from` to `to`.\r\n     *\r\n     * This internal function is equivalent to {transfer}, and can be used to\r\n     * e.g. implement automatic token fees, slashing mechanisms, etc.\r\n     *\r\n     * Emits a {Transfer} event.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `from` cannot be the zero address.\r\n     * - `to` cannot be the zero address.\r\n     * - `from` must have a balance of at least `amount`.\r\n     */\r\n\r\n    /**\r\n     * @dev Destroys `amount` tokens from `account`, reducing the\r\n     * total supply.\r\n     *\r\n     * Emits a {Transfer} event with `to` set to the zero address.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `account` cannot be the zero address.\r\n     * - `account` must have at least `amount` tokens.\r\n     */\r\n    function _burn(address account, uint256 amount) internal virtual {\r\n        require(account != address(0), \"ERC20: burn from the zero address\");\r\n\r\n        _beforeTokenTransfer(account, address(0), amount);\r\n\r\n        uint256 accountBalance = _balances[account];\r\n        require(accountBalance >= amount, \"ERC20: burn amount exceeds balance\");\r\n        unchecked {\r\n            _balances[account] = accountBalance - amount;\r\n            // Overflow not possible: amount <= accountBalance <= totalSupply.\r\n            _totalSupply -= amount;\r\n        }\r\n\r\n        emit Transfer(account, address(0), amount);\r\n\r\n        _afterTokenTransfer(account, address(0), amount);\r\n    }\r\n\r\n    function decreaseAllowance(address spender, uint256 subtractedValue)\r\n        public\r\n        virtual\r\n        returns (bool)\r\n    {\r\n        address owner = _msgSender();\r\n        uint256 currentAllowance = allowance(owner, spender);\r\n        require(\r\n            currentAllowance >= subtractedValue,\r\n            \"ERC20: decreased allowance below zero\"\r\n        );\r\n        unchecked {\r\n            _approve(owner, spender, currentAllowance - subtractedValue);\r\n        }\r\n\r\n        return true;\r\n    }\r\n\r\n    function _spendAllowance(\r\n        address owner,\r\n        address spender,\r\n        uint256 amount\r\n    ) internal virtual {\r\n        uint256 currentAllowance = allowance(owner, spender);\r\n        if (currentAllowance != type(uint256).max) {\r\n            require(\r\n                currentAllowance >= amount,\r\n                \"ERC20: insufficient allowance\"\r\n            );\r\n            unchecked {\r\n                _approve(owner, spender, currentAllowance - amount);\r\n            }\r\n        }\r\n    }\r\n    /**\r\n     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.\r\n     *\r\n     * This internal function is equivalent to `approve`, and can be used to\r\n     * e.g. set automatic allowances for certain subsystems, etc.\r\n     *\r\n     * Emits an {Approval} event.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - `owner` cannot be the zero address.\r\n     * - `spender` cannot be the zero address.\r\n     */\r\n    function _approve(\r\n        address owner,\r\n        address spender,\r\n        uint256 amount\r\n    ) internal virtual {\r\n        require(owner != address(0), \"ERC20: approve from the zero address\");\r\n        require(spender != address(0), \"ERC20: approve to the zero address\");\r\n\r\n        _allowances[owner][spender] = amount;\r\n        emit Approval(owner, spender, amount);\r\n    }\r\n\r\n    function _beforeTokenTransfer(\r\n        address from,\r\n        address to,\r\n        uint256 amount\r\n    ) internal virtual {}\r\n\r\n    /**\r\n     * @dev Hook that is called after any transfer of tokens. This includes\r\n     * minting and burning.\r\n     *\r\n     * Calling conditions:\r\n     *\r\n     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens\r\n     * has been transferred to `to`.\r\n     * - when `from` is zero, `amount` tokens have been minted for `to`.\r\n     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.\r\n     * - `from` and `to` are never both zero.\r\n     *\r\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\r\n     */\r\n    function _afterTokenTransfer(\r\n        address from,\r\n        address to,\r\n        uint256 amount\r\n    ) internal virtual {}\r\n    /**\r\n     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.\r\n     *\r\n     * Does not update the allowance amount in case of infinite allowance.\r\n     * Revert if not enough allowance is available.\r\n     *\r\n     * Might emit an {Approval} event.\r\n     */\r\n\r\n    /**\r\n     * @dev Hook that is called before any transfer of tokens. This includes\r\n     * minting and burning.\r\n     *\r\n     * Calling conditions:\r\n     *\r\n     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens\r\n     * will be transferred to `to`.\r\n     * - when `from` is zero, `amount` tokens will be minted for `to`.\r\n     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.\r\n     * - `from` and `to` are never both zero.\r\n     *\r\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\r\n     */\r\n}\r\n\r\n// OpenZeppelin Contracts (last updated v4.6.0) (utils/math/SafeMath.sol)\r\n\r\n\r\n/**\r\n * @dev Wrappers over Solidity's arithmetic operations.\r\n *\r\n * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler\r\n * now has built in overflow checking.\r\n */\r\nlibrary SafeMath {\r\n    /**\r\n     * @dev Returns the division of two unsigned integers, with a division by zero flag.\r\n     *\r\n     * _Available since v3.4._\r\n     */\r\n    function tryDiv(uint256 a, uint256 b)\r\n        internal\r\n        pure\r\n        returns (bool, uint256)\r\n    {\r\n        unchecked {\r\n            if (b == 0) return (false, 0);\r\n            return (true, a / b);\r\n        }\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.\r\n     *\r\n     * _Available since v3.4._\r\n     */\r\n    function tryMul(uint256 a, uint256 b)\r\n        internal\r\n        pure\r\n        returns (bool, uint256)\r\n    {\r\n        unchecked {\r\n            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the\r\n            // benefit is lost if 'b' is also tested.\r\n            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522\r\n            if (a == 0) return (true, 0);\r\n            uint256 c = a * b;\r\n            if (c / a != b) return (false, 0);\r\n            return (true, c);\r\n        }\r\n    }\r\n    /**\r\n     * @dev Returns the addition of two unsigned integers, with an overflow flag.\r\n     *\r\n     * _Available since v3.4._\r\n     */\r\n\r\n    /**\r\n     * @dev Returns the subtraction of two unsigned integers, with an overflow flag.\r\n     *\r\n     * _Available since v3.4._\r\n     */\r\n    function trySub(uint256 a, uint256 b)\r\n        internal\r\n        pure\r\n        returns (bool, uint256)\r\n    {\r\n        unchecked {\r\n            if (b > a) return (false, 0);\r\n            return (true, a - b);\r\n        }\r\n    }\r\n\r\n    function tryAdd(uint256 a, uint256 b)\r\n        internal\r\n        pure\r\n        returns (bool, uint256)\r\n    {\r\n        unchecked {\r\n            uint256 c = a + b;\r\n            if (c < a) return (false, 0);\r\n            return (true, c);\r\n        }\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),\r\n     * reverting when dividing by zero.\r\n     *\r\n     * Counterpart to Solidity's `%` operator. This function uses a `revert`\r\n     * opcode (which leaves remaining gas untouched) while Solidity uses an\r\n     * invalid opcode to revert (consuming all remaining gas).\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - The divisor cannot be zero.\r\n     */\r\n    function mod(uint256 a, uint256 b) internal pure returns (uint256) {\r\n        return a % b;\r\n    }\r\n    /**\r\n     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.\r\n     *\r\n     * _Available since v3.4._\r\n     */\r\n    function tryMod(uint256 a, uint256 b)\r\n        internal\r\n        pure\r\n        returns (bool, uint256)\r\n    {\r\n        unchecked {\r\n            if (b == 0) return (false, 0);\r\n            return (true, a % b);\r\n        }\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the addition of two unsigned integers, reverting on\r\n     * overflow.\r\n     *\r\n     * Counterpart to Solidity's `+` operator.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - Addition cannot overflow.\r\n     */\r\n    function add(uint256 a, uint256 b) internal pure returns (uint256) {\r\n        return a + b;\r\n    }\r\n\r\n    /**\r\n     * @dev Returns the integer division of two unsigned integers, reverting on\r\n     * division by zero. The result is rounded towards zero.\r\n     *\r\n     * Counterpart to Solidity's `/` operator.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - The divisor cannot be zero.\r\n     */\r\n\r\n    /**\r\n     * @dev Returns the subtraction of two unsigned integers, reverting on\r\n     * overflow (when the result is negative).\r\n     *\r\n     * Counterpart to Solidity's `-` operator.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - Subtraction cannot overflow.\r\n     */\r\n    function sub(uint256 a, uint256 b) internal pure returns (uint256) {\r\n        return a - b;\r\n    }\r\n\r\n    /**\r\n     * - The divisor cannot be zero.\r\n     */\r\n    function mod(\r\n        uint256 a,\r\n        uint256 b,\r\n        string memory errorMessage\r\n    ) internal pure returns (uint256) {\r\n        unchecked {\r\n            require(b > 0, errorMessage);\r\n            return a % b;\r\n        }\r\n    }\r\n    /**\r\n     * @dev Returns the multiplication of two unsigned integers, reverting on\r\n     * overflow.\r\n     *\r\n     * Counterpart to Solidity's `*` operator.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - Multiplication cannot overflow.\r\n     */\r\n    function mul(uint256 a, uint256 b) internal pure returns (uint256) {\r\n        return a * b;\r\n    }\r\n\r\n\r\n    /**\r\n     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on\r\n     * overflow (when the result is negative).\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - Subtraction cannot overflow.\r\n     */\r\n    function sub(\r\n        uint256 a,\r\n        uint256 b,\r\n        string memory errorMessage\r\n    ) internal pure returns (uint256) {\r\n        unchecked {\r\n            require(b <= a, errorMessage);\r\n            return a - b;\r\n        }\r\n    }\r\n    function div(uint256 a, uint256 b) internal pure returns (uint256) {\r\n        return a / b;\r\n    }\r\n\r\n\r\n    /**\r\n     * @dev Returns the integer division of two unsigned integers, reverting with custom message on\r\n     * division by zero. The result is rounded towards zero.\r\n     *\r\n     * Requirements:\r\n     *\r\n     * - The divisor cannot be zero.\r\n     */\r\n    function div(\r\n        uint256 a,\r\n        uint256 b,\r\n        string memory errorMessage\r\n    ) internal pure returns (uint256) {\r\n        unchecked {\r\n            require(b > 0, errorMessage);\r\n            return a / b;\r\n        }\r\n    }\r\n}\r\n\r\ncontract BookOfEth is ERC20, Ownable {\r\n    constructor() ERC20(\"Book of Ethereum\", \"BOOE\")\r\n    {\r\n        uint256 totalSupply = 100_000_000 * (10 ** 18);\r\n        _mint(owner(), totalSupply);\r\n    }\r\n}"
      }
    },
    "settings": {
      "optimizer": {
        "enabled": false,
        "runs": 200
      },
      "outputSelection": {
        "*": {
          "*": [
            "evm.bytecode",
            "evm.deployedBytecode",
            "devdoc",
            "userdoc",
            "metadata",
            "abi"
          ]
        }
      },
      "libraries": {}
    }
  }}