#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  vector<int> cnt(10, 0);
  for (int i = 0; i < N; i++){
    int a, b, c;
    cin >> a >> b >> c;
    cnt[a - 1]++;
    cnt[b - 1]++;
    cnt[c - 1]++;
  }
  int ans = 0;
  for (int i = 0; i < 10; i++){
    ans += cnt[i] / 2;
    cnt[i] %= 2;
  }
  int sum = 0;
  for (int i = 0; i < 10; i++){
    sum += cnt[i];
  }
  ans += sum / 4;
  cout << ans << endl;
}