#include <bits/stdc++.h>
#define ll long long
using namespace std;
int main() {
    int T, n, m;
    scanf("%d", &T);
    while(T--) {
        scanf("%d%d", &n, &m), m = min(m, n / 2);
        int R = 2 * n - 3, L = R - (m - 1) * 4;
        printf("%lld\n", 1LL * (L + R) * m / 2);
    }
    return 0;
}