#include <iostream>
#define test cout << "test";
using namespace std;

int main(void){
  int item[9],temp;
  cin >> temp;
  const int num = temp;
  for(int i = 0; i < 9; i++)item[i] = 0;
  for(int i = 0; i < num; i++){
    for(int j = 0; j < 3; j++){
      cin >> temp;
      item[temp - 1]++;
    }
  }
  int count = 0;
  temp = 0;
  for(int i = 0; i < 9; i++){
    while(item[i] >= 2){
      count++;
      item[i] -= 2;
    }
    if(item[i] == 1)temp++;
  }
  cout << count + temp / 4 << endl;
  return 0;
}