#include<stdio.h>
int main()
{
	int n;
	scanf("%d", &n);
	int i;
	int count[11];
	for (i = 0; i < 11; i++)
		count[i] = 0;
	int a, b, c;
	for (i = 0; i < n; i++)
	{
		scanf("%d %d %d", &a, &b, &c);
		count[a]++;
		count[b]++;
		count[c]++;
	}
	int ans = 0;
	for (i = 0; i < 11; i++)
	{
		ans += count[i] / 2;
		count[i] %= 2;
	}
	int sum = 0;
	for (i = 0; i < 11; i++)
		sum += count[i];
	ans += sum / 4;
	printf("%d\n", ans);
	return 0;
}