#include <iostream>
using namespace std;

int main()
{
	int N;
	int item;
	int count[10] = {0};
	int answer = 0;

	cin >> N;
	for(int i = 0; i < N; ++i)
	{
		for(int j = 0; j < 3; ++j)
		{
			cin >> item;
			count[item - 1]++;
		}
	}

	for(int i = 0; i < 10; ++i)
	{
		answer += count[i] / 2;
	}
	answer += ((N * 3) - (answer * 2)) / 4;

	cout << answer << endl;

	return 0;
}