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

using ll = long long;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int T;
    cin >> T;
    assert(1 <= T && T <= 100000);
    while (T--)
    {
        ll N, M;
        cin >> N >> M;

        assert(0 <= N && N <= 1000000000LL);
        assert(0 <= M && M <= 1000000000LL);

        if (N % 2 == 1) N--;
        if (M % 2 == 1) M--;

        if (N < 2 * M)
        {
            cout << (3 * (N / 4)) << endl;
        }
        else
        {
            ll ans = 3 * (M / 2);
            N -= 2 * M;
            M = 0;
            ans += 6 * (N / 10);
            N %= 10;
            if (6 <= N) ans += 3;

            cout << ans << endl;
        }
    }
}