#include <stdio.h>

int main() {
	int n, a, b, c, cnt[10] = {}, cnt2 = 0, sum = 0, i;

	scanf("%d", &n);
	for (i = 0; i < n; i++) {
		scanf("%d %d %d", &a, &b, &c);
		cnt[a - 1]++;
		cnt[b - 1]++;
		cnt[c - 1]++;
	}
	for (i = 0; i < 10; i++) {
		sum += cnt[i] / 2;
		cnt2 += cnt[i] % 2;
	}

	printf("%d\n", sum + cnt2 / 4);
	return 0;
}