#include <bits/stdc++.h>

using namespace std;

void test_case(int tc){
    int n, m;
    cin >> n >> m;

    int distance = 0;

    for(int i = 0; i < n; ++i){
        int a;
        cin >> a;

        distance += a;
    }

    cout << max(0, distance - m) << '\n';
}



int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);

    int t;
    cin >> t;

    for(int tc = 1; tc <= t; ++tc){
        test_case(tc);
    }

    cout << flush;

    return 0;
}