#include <iostream>
#include <vector>
using namespace std;

int main() {
	int n;
	cin >> n;

	vector<int> count_items(10 + 1, 0);
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < 3; j++) {
			int item;
			cin >> item;
			count_items[item]++;
		}
	}

	int ans = 0;
	int sum = 0;
	for (int i = 1; i < count_items.size(); i++) {
		ans += count_items[i] / 2;
		sum += count_items[i] % 2;
	}
	ans += sum / 4;

	cout << ans << endl;

	return 0;
}