#include <bits/stdc++.h>

using namespace std;

int main() {
  int n;
  cin >> n;
  int v[10]{};
  int res = 0, sum = 3 * n;
  for (int i = 0; i < 3 * n; ++i) {
    int a;
    cin >> a;
    --a;
    ++v[a];
    if (v[a] == 2) {
      ++res;
      sum -= 2;
      v[a] = 0;
    }
  }
  cout << res + sum / 4 << endl;
}