#include <bits/stdc++.h>

using namespace std;

int main() {
    int t;
    cin >> t;
    while (t--) {
    int n, k;
    cin >> n >> k;
    int a, mk=INT_MAX;
    long long int num = 1;
    for (int i=0; i<n; i++) {
        cin >> a;
        num *= a;
        mk = min(mk, a);
    }
    a = mk - k;
    num /= mk;
    num *= a;
    cout << num << endl;
}
    return 0;
}