#include<iostream>
using namespace std;

int nlist[10];
int level;

int main(){
  int N;
  cin>>N;
  for(int i=0;i<N;i++){
    int a,b,c;
    cin>>a>>b>>c;
    nlist[a-1]++;
    nlist[b-1]++;
    nlist[c-1]++;
  }
  int temp=0;
  for(int i=0;i<10;i++){
    if(nlist[i] >= 2){
      level += nlist[i]/2;
    }
    temp += nlist[i]%2;
  }
  cout<<level+temp/4<<endl;
  return 0;
}