#include <bits/stdc++.h>
using namespace std;
int N, a, b, c, i, x, y, I[11] = {};
int main() {
  cin >> N;
  while (N-- && cin >> a >> b >> c) I[a]++, I[b]++, I[c]++;
  for (int i = 1; i < 11; i++) x += I[i] / 2, y += I[i] % 2;
  cout << x + y / 4 << "\n";
}