```\nfunction getTokenAmountOut(uint256 amountBNBIn)\n    external\n    view\n    returns (uint256)\n{\n    uint256 amountAfter = liqConst / (liquidity - amountBNBIn);\n    uint256 amountBefore = liqConst / liquidity;\n    return amountAfter - amountBefore;\n}\n```\n