#include <iostream>

using namespace std;

int main()
{
    int n;
    int num[11] = {0};
    int item = 0;
    int ans = 0;

    cin >> n;

    for (int i = 0; i < n; i++) {
        int a, b, c;

        cin >> a >> b >> c;
        num[a]++;
        num[b]++;
        num[c]++;
    }

    for (int i = 1; i <= 10; i++) {
        if (num[i]%2) {
            item++;
            ans += num[i]/2;
        }
        else {
            ans += num[i]/2;
        }
    }

    cout << ans + (item/4) << endl;
}