#include <bits/stdc++.h>
#define rep(i, ss, ee) for (int i = ss; i < ee; ++i)
using namespace std;

int main() {
  int N, a, b, c;
  cin >> N;
  vector<int> v(11);
  rep(i, 0, N) {
    cin >> a >> b >> c;
    v[a]++, v[b]++, v[c]++;
  }
  int ans = 0, cnt = 0;
  for (auto n : v) {
    ans += n / 2;
    cnt += n % 2;
  }
  ans += cnt / 4;
  cout << ans << endl;
  getchar();
}