#include <bits/stdc++.h>

using namespace std;

using pii = pair<int, int>;
using ll = long long;
const int N = 2000010, MOD = 998244353, INF = 0x3f3f3f3f;
int n, m, w[N];

void solve() {
    scanf("%d%d", &n, &m);
    int l = 0, r = n;
    while (l < r) {
        int mid = l + r + 1 >> 1;
        ll pa = n - 4ll * mid, pb = m - 2ll * mid;
        if (pa > 0) {
            pb += pa * 2 - (pa & 1) * 2;
            pa = 0;
        }
        if (pa >= 0 && pb >= 0) l = mid;
        else r = mid - 1;
    }
    printf("%d\n", l * 3);
}

int main() {
    int T = 1;
    scanf("%d", &T);
    while (T--) solve();
    return 0;
}