#include <bits/stdc++.h>

using namespace std;

int main() {
  int n;
  cin >> n;
  map<int, int> m;
  int ans = 0;
  for (int i = 0; i < n; ++i) {
    int a, b, c;
    cin >> a >> b >> c;
    m[a]++; m[b]++; m[c]++;
    if (m[a] >= 2) {
      m[a] -= 2;
      ans++;
    }
    if (m[b] >= 2) {
      m[b] -= 2;
      ans++;
    }
    if (m[c] >= 2) {
      m[c] -= 2;
      ans++;
    }
  }

  int cnt = 0;
  for (auto &e: m) {
    cnt += e.second;
  }

  ans += cnt / 4;
  cout << ans << '\n';
  return 0;
}