#include <stdio.h>

int main()
{
	int n;
	scanf("%d", &n);

	int bag[10] = {0};

	for (int i = 0; i < n * 3; i++)
	{
		int items;
		scanf("%d", &items);

		bag[items - 1]++;
	}

	int limited = 0, pow = 0;

	for (int i = 0; i < 10; i++)
	{
		while (bag[i] >= 2)
		{
			bag[i] += -2;
			pow++;
		}

		limited += bag[i];
	}

	while (limited >= 4)
	{
		limited += -4;
		pow++;
	}

	printf("%d", pow);

	return 0;
}