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

int main() {
  vector<int> I(11);
  int N;
  cin >> N;
  for (int i = 0, a, b, c; i < N && cin >> a >> b >> c; i++) I.at(a)++, I.at(b)++, I.at(c)++;
  int x = 0, y = 0;
  for (int i = 1; i < 10; i++) x += I.at(i) / 2, y += I.at(i) % 2;
  cout << x + y / 4 << "\n";
}