#include<stdio.h>

int main() {
	
	int enemyNum = 0;
	int dropItem[3] = { 0,0,0 };
	int myItem[10] = { 0,0,0,0,0,0,0,0,0,0 };

	scanf("%d", &enemyNum);

	for (int i = 0; i < enemyNum; i++) {
		scanf("%d %d %d", &dropItem[0], &dropItem[1], &dropItem[2]);

		for (int j = 0; j < 3; j++)
			myItem[dropItem[j] - 1]++;
	}

	int supItem = 0;
	int powerUp = 0;

	for (int i = 0; i < 10; i++) {
		supItem += myItem[i] % 2;
		powerUp += myItem[i] / 2;
	}

	printf("%d\n", powerUp + supItem / 3);

	// 終了コードは0
	return 0;
}