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

template<typename T>
void fin(T a){
  cout<<a<<endl;
  exit(0);
}
signed main(){
    int n;cin>>n;n*=3;
    map<int,int> m;
    while(n--){
        int a;cin>>a;m[a]++;
    }
    int ans=0,cnt=0;
    for(auto p:m){
        ans+=p.second>>1;
        cnt+=p.second&1;
    }
    cout<<ans+cnt/4<<endl;
}