#include <iostream>
#include <map>
using namespace std;
int main(){
        int N;
        cin >> N;
        map<int,int> item;
        int counter=0;
        for(int i=0 ; i<N ; i++ ){
                int x;
                cin >> x;item[x]++;
                if(item[x]>1){
                        counter++;
                        item[x]-=2;
                }
                cin >> x;item[x]++;
                if(item[x]>1){
                        counter++;
                        item[x]-=2;
                }
                cin >> x;item[x]++;
                if(item[x]>=2){
                        counter++;
                        item[x]-=2;
                }
        }
//      cout << N*3 << " "<<counter << endl;
        if((2*counter)<(N*3))
                cout << counter+((N*3)-(2*counter))/4 << endl;
        else
                cout<<counter << endl;
        return 0;
}