#include <iostream>
using namespace std;
int n, t, item, ans, a[11];

int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < 3; j++) {
      cin >> t;
      a[t]++;
    }
  }
  for (int i = 1; i <= 10; i++) {
    if (a[i] / 2) {
      ans += a[i] / 2;
      item += a[i] % 2;
    } else if (a[i]) {
      item++;
    }
  }
  ans += item / 4;
  cout << ans << endl;
}