function calculateSwap(
    uint256 amountIn,
    uint256 reserveIn,
    uint256 reserveOut
) public pure returns (uint256 amountOut) {
    // x * Y * X
    uint256 numerator = amountIn * reserveIn * reserveOut;

    // (x + X) ^ 2
    uint256 denominator = pow(amountIn + reserveIn);

    amountOut = numerator / denominator;
}
