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

void answer() {
    int n, m;
    cin >> n >> m;
    int z;
    z = (n - (2 * m)) / 10;
    if (z < 0) {
    	z = 0;
    }
    n -= 2 * z;
    m += 4 * z;
    int a = min((m / 2),(n / 4));
    a = max (a, min(((n - 2) / 4), (m + 4) / 2));
    cout << 3 * a << endl;
    return;
}

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