#include<bits/stdc++.h>
using namespace std;
using Int = long long;
//INSERT ABOVE HERE
signed main(){
  Int n;
  cin>>n;
  vector<Int> cnt(11,0);
  for(Int i=0;i<n;i++){
    Int a,b,c;
    cin>>a>>b>>c;
    cnt[a]++;
    cnt[b]++;
    cnt[c]++;	    
  }
  Int ans=0,sum=0;
  for(Int i=0;i<11;i++){
    ans+=cnt[i]/2;
    sum+=cnt[i]&1;
  }
  ans+=sum/4;
  cout<<ans<<endl;
  return 0;
}