#include <iostream>

using namespace std;

int main()
{
	int N, a, b, c, pow, sum, item[11] = { 0 };

	cin >> N;
	for (int i = 0; i < N; i++) {
		cin >> a >> b >> c;
		item[a]++; item[b]++; item[c]++;
	}

	pow = sum = 0;
	for (int i = 1; i <= 10; i++) {
		while (item[i] >= 2) {
			pow++;
			item[i] -= 2;
		}
		sum += item[i];
	}

	pow += sum / 4;

	cout << pow << endl;

	return 0;
}