#include <iostream>
using namespace std;

int main()
{
    int N;
    cin >> N;
    
    int a,b,c;
    int item[11] = {};
    for(int i = 0; i < N; i++){
        cin >> a >> b >> c;
        item[a]++;
        item[b]++;
        item[c]++;
    }
    
    int same2 = 0,differ= 0;
    for(int i = 1; i <= 10; i++){
        same2 += item[i] / 2;
        differ += item[i] % 2;
    }

    cout << same2 + (differ / 4) << endl;

    return 0;
}