#include<iostream>
#include<algorithm>
#include<stdio.h>
#include<stdlib.h>
#include<vector>
#include<string>
#include<sstream>
#include<math.h>
using namespace std;


int main(){

  int n;
  cin >> n;
  vector<int> itm(10);

  for(int i=0;i<n;i++){
    int tmp[3];
    cin >> tmp[0] >> tmp[1] >> tmp[2];

    itm[tmp[0]-1]++;
    itm[tmp[1]-1]++;
    itm[tmp[2]-1]++;
  }

  int cnt=0;
  int fl=0;
  for(int i=0;i<10;i++){
    if( itm[i]%2 == 0 ){
      cnt += itm[i]/2;
    }else{
      cnt += itm[i]/2;
      fl++;
    }
  }
  cnt += fl/4;

  cout << cnt << endl;

  return 0;
}