#include <iostream>

using namespace std;

int N, a, b, c;
int cnt[10];

int main() {
	cin >> N;
	for (int i = 0; i < N; i++) {
		cin >> a >> b >> c;
		cnt[a - 1]++;
		cnt[b - 1]++;
		cnt[c - 1]++;
	}
	int res = 0;
	int rest = 0;
	for (int i = 0; i < 10; i++) {
		res += cnt[i] / 2;
		rest += cnt[i] % 2;
	}
	res += rest / 4;
	cout << res << endl;
	return 0;
}