/* -*- coding: utf-8 -*-
 *
 * 3534.cc:  No.3534 Make Many Fences - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

/* typedef */

using ll = long long;

/* global variables */

/* subroutines */

ll calc(int n, int m, int d) {
  ll nn = n - d, mm = m + (ll)(d / 2) * 4;
  ll f = min(nn / 4, mm / 2) * 3;
  return f;
}

/* main */

int main() {
  int tn;
  scanf("%d", &tn);

  while (tn--) {
    int n, m;
    scanf("%d%d", &n, &m);

    int d0 = 0, d1 = n;
    while (d0 + 2 < d1) {
      int dd0 = (d0 * 2LL + d1) / 3;
      int dd1 = (d0 + d1 * 2LL) / 3;
      ll f0 = calc(n, m, dd0);
      ll f1 = calc(n, m, dd1);
      if (f0 < f1) d0 = dd0;
      else d1 = dd1;
    }

    ll maxf = 0;
    for (int d = d0; d <= d1; d++)
      maxf = max(maxf, calc(n, m, d));

    printf("%lld\n", maxf);
  }

  return 0;
}