#include <iostream>
#include <list>
#include <vector>
#include <string>
#include <stdio.h>
#include <stdint.h>
using namespace std;

using uint = unsigned int;
using ll = long long;

int main()
{

  ll N;
  cin >> N;

  ll A;
  ll B;
  ll C;
  ll item[11] = {};  
  
  for( ll i = 0 ; i < N ; i++ ){

    cin >> A;
    cin >> B;
    cin >> C;
    item[A]++;
    item[B]++;
    item[C]++;
    
  }

  ll answer = 0;
  ll sum = 0;
  
  for( ll j = 1 ; j <= 10 ; j++ ){

    const ll& n = item[j];
    answer += n / 2;
    sum += n % 2;
    
  }

  answer += sum / 4;
  cout << answer << endl;
  return 0;

}