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

int main() {
  int N;
  cin >> N;
  vector<int> a(N), b(N), c(N);
  for (int i = 0; i < N; i++)
    cin >> a[i] >> b[i] >> c[i];
  int item[11] = {};
  for (int i = 0; i < N; i++)
    item[a[i]]++, item[b[i]]++, item[c[i]]++;
  int ans = 0, kind = 0;
  for (int i = 1; i <= 10; i++)
    ans += item[i] / 2, item[i] -= item[i] / 2 * 2;
  for (int i = 1; i <= 10; i++)
    if (item[i] == 1)
      kind++;
  ans += kind / 4;
  cout << ans << endl;
}