WeirdLoop.sol

contract A {
    uint[10] list = [1,2,3,4,5,6,7,8,9,10];
    
    function loop(uint _n) public view returns (uint) {
        uint sum = 0;
        
        uint start = list.length - 1;
        uint end = list.length - _n;
        
        for (uint i = start; i >= end; i--) {
            sum += list[i];
        }
        return sum;
    }
}