#include <iostream>
using namespace std;

int main(void){
    int N, a, b, c, i, count = 0, lvl = 0;
    int items[10] = {0};

    cin >> N;
    for(i=0; i<N; i++){
        cin >> a >> b >> c;
        items[a-1]++;
        items[b-1]++;
        items[c-1]++;
    }
    for(i=0; i<10; i++){
        lvl += items[i] / 2;
        count += items[i] % 2;
    }
    lvl += count / 4;
    cout << lvl << endl;

    return 0;
}