library CastI128U128 {
    /// @dev Safely cast an int128 to an uint128
    function u128(int128 x) internal pure returns (uint128 y) {
        require (x >= 0, "Cast overflow");
        y = uint128(x);
    }
}
function u128(int128 x) internal pure returns (uint128 y) {
    require (x >= 0, "Cast overflow");
    y = uint128(x);
}

/// @dev Safely cast an int128 to an uint128