#include <iostream>
#include <array>

using namespace std;
int main() {


  int N,sum,m;
  sum = 0;
  m = 0;
  array<int,10> t;
  t = {0,0,0,0,0,0,0,0,0,0};
  cin >> N;
  for (int i = 0; i < N; i++) {
    int a,b,c;
    cin >> a >> b >> c;
    t[a-1] = t[a-1] + 1;
    t[b-1] = t[b-1] + 1;
    t[c-1] = t[c-1] + 1;
  }
  for (int i = 0; i < 10; i++) {
    sum += t[i] / 2;
  }
  for (int i = 0; i < 10; i++) {
    m += t[i] % 2;
  }
  sum += m / 4;
  cout << sum << "\n";
  return 0;
}