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

int main() {

	int N, Item[10];
	cin >> N;
	for (int i = 0; i < 10; i++)	Item[i] = 0;

	for (int i = 0; i < N; i++)
	{
		int a, b, c;
		cin >> a >> b >> c;
		Item[a-1] += 1;
		Item[b-1] += 1;
		Item[c-1] += 1;
	}

	int q = 0, r = 0, ans = 0;
	for (int i = 0; i < 10; i++)
	{
		q += (Item[i] / 2);
		r += (Item[i] % 2);
	}
	ans += q + (r / 4);
	cout << ans << endl;

	return 0;
}