#include <bits/stdc++.h>
using namespace std;
using ll = long long;

void answer() {
    int n, m;
    cin >> n >> m;
    while (n > (2 * m)) {
        n -= 2;
        m += 4;
    }
    cout << 3 * (n / 4) << endl;
    return;
}

int main() {
    int t;
    cin >> t;
    for (int i = 0; i < t; i++) {
        answer();
    }
    return 0;
}