#include "bits/stdc++.h"
using namespace std;

int main() {
	int N, a, b, c, Item[10] = {}, sum = 0, count = 0;
	cin >> N;
	for (int i = 0; i < N; i++) {
		cin >> a >> b >> c;
		Item[a - 1]++;
		Item[b - 1]++;
		Item[c - 1]++;
	}
	for (int i = 0; i < 10; i++) {
		count += Item[i] / 2;
		Item[i] = Item[i] % 2;
		sum += Item[i];
	}
	count += sum / 4;
	cout << count << endl;
}