#include <iostream>
using namespace std;
int main() {
	int item[10] = { 0 };
	int N;
	int item_num = 0;
	int up_times = 0;
	cin >> N;
	for (int i = 0; i < N;i++) {
		int a, b, c;
		cin >> a >> b >> c;
		if (++item[a - 1] == 2) { up_times++; item[a - 1] = 0; }
		if (++item[b - 1] == 2) { up_times++; item[b - 1] = 0; }
		if (++item[c - 1] == 2) { up_times++; item[c - 1] = 0; }
	}
	for (int i = 0; i < 10;i++) {
		item_num += item[i];
	}
	up_times += (item_num / 4);
	cout << up_times << endl;
	return 0;
}