#include <bits/stdc++.h>
using namespace std;

int main() {
  int N;
  cin >> N;
  int ans = 0;
  vector<int> cnt(10, 0);
  for (int i = 0; i < N; i++) {
    int a, b, c;
    cin >> a >> b >> c;
    a--;
    b--;
    c--;
    cnt[a]++;
    cnt[b]++;
    cnt[c]++;
  }
  int tmp = 0;
  for (int i = 0; i < 10; i++) {
    ans += cnt[i] / 2;
    tmp += cnt[i] % 2;
  }
  ans += tmp / 4;
  printf("%d\n", ans);
  return 0;
}