#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int tc;
  cin >> tc;
  int z;
  for (int t = 1; t <= tc; t++) {
    cin >> z;
    int a, s, d = 0;
    s = 0;
    a = 0;
    int x;
    for (int q = 1; q <= z; q++) {
      cin >> x;
      if (x % 3 == 0)
        a++;
      else if (x % 3 == 1)
        s++;
      else
        d++;
    }
    int total = a + (min(s, d));
    int temp = min(s, d);
    s -= temp;
    d -= temp;
    total += (s / 3);
    total += (d / 3);
    cout << total << endl;
  }
}
