#include <iostream>
#include <algorithm>
#include <cstdio>
#include <string>

#define ll long long

using namespace std;

int Item[11];

int main(){
  
  int n,a,b,c;
  cin>>n;
  for(int i=0;i<n;++i){
     cin>>a>>b>>c;
     Item[a]++;
     Item[b]++;
     Item[c]++;
  }
  
  int ans=0;
  for(int i=1;i<=10;++i){
     ans+=Item[i]/2;
     Item[i]%=2;    
  }
  
  int rest=0;
  for(int i=1;i<=10;++i) rest+=Item[i];
  ans+=rest/4;

  cout<<ans<<endl;

  return 0;
}