#include<iostream>

using namespace std;

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

	int itemNO[10] = { 0 };

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

	int twoup = 0, fourup = 0;;
	for (int i = 0; i < 10; i++){
		twoup += itemNO[i] / 2;
		fourup += itemNO[i] % 2;
	}

	int powerup = 0;
	powerup = twoup + (fourup / 4);

	cout << powerup << endl;

}