#include <bits/stdc++.h>
#define rep(i, a, n) for (int i = a; i < n; i++)
#define repr(i, a, n) for (int i = n - 1; i >= a; i--)
using namespace std;
using ll = long long;
using P = pair<int, int>;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);

  int n;
  cin >> n;
  vector<int> v(11);

  rep(i, 0, n) {
    int a, b, c;
    cin >> a >> b >> c;
    v[a]++;
    v[b]++;
    v[c]++;
  }

  int ans = 0;
  rep(i, 1, 11) {
    if (v[i] >= 2) {
      ans += v[i] / 2;
      v[i] %= 2;
    }
  }

  int sum_val = 0;
  rep(i, 1, 11) {
    if (v[i] == 1) sum_val++;
    if (sum_val == 4) {
      ans++;
      sum_val = 0;
    }
  }

  cout << ans << endl;
}