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

int main(){
  int n;
  cin>>n;
  map<int,int>mp;
  for(int i=0;i<n;i++){
    int p,q,r;
    cin>>p>>q>>r;
    mp[p]++;
    mp[q]++;
    mp[r]++;
  }
  int cnt=0;
  int mod=0;
  for(auto itr=mp.begin();itr != mp.end();itr++){
    cnt+=(itr->second)/2;
    mod+=(itr->second)%2;
    if(mod>=4){
      cnt++;
      mod-=4;
    }
  }
  cout<<cnt<<endl;
  return 0;
}