#include <iostream>
#include <vector>

using namespace std;

int main()
{
	int N;
	vector<int> item(11, 0);
	int tmp;
	cin >> N;
	for( int i = 0; i < N; i++ ) {
		cin >> tmp;
		item[tmp] ++;
		cin >> tmp;
		item[tmp] ++;
		cin >> tmp;
		item[tmp] ++;
	}

	int p = 0;
	int rest = 0;
	for( int i = 1; i <= 10; i++ ) {
		p += item[i] / 2;
		rest += item[i] % 2;
	}
	p += rest / 4;

	cout << p << endl;



	return 0;
}