#include <bits/stdc++.h>
using namespace std;
#define int long long int

void solve() {
    int n, k;
    cin >> n >> k;

    // Compute best Y (target value)
    int bestTarget = k / (n + 1);

    // Compute X = K - N * bestTarget
    int X = k - n * bestTarget;

    // Final answer is X * bestTarget
    int ans = X * bestTarget;

    cout << ans << endl;
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int test;
    cin >> test;
    while (test--) {
        solve();
    }

    return 0;
}