#include<iostream>
using namespace std;

int main()
{
    int item[11] = {0};
    int N, n, cnt = 0;
    int power = 0;

    cin >> N;
    for(int i=0; i<N; i++){
        for(int j=0; j<3; j++){
            cin >> n;
            if(item[n] == 1){
                power++;
                item[n] = 0;
            }else item[n] = 1;
        }
    }
    for(int i=1; i<11; i++){
        if(item[i] == 1) cnt++;
    }
    power += cnt/4;
    cout << power << endl;

    return 0;
}