#include <iostream>
#include <vector>
using namespace std;

int main()
{
	int N;

	while( cin >> N ){
		vector< int > item( 10, 0 );
		for( int i = 0; i < N; ++i ){
			int a, b, c;
			cin >> a >> b >> c;
			item[ a - 1 ]++;
			item[ b - 1 ]++;
			item[ c - 1 ]++;
		}
		int up = 0;
		int rest = 0;
		for( int i = 0; i < 10; ++i ){
			up += item[ i ] / 2;
			rest += item [ i ] % 2;
		}
		up += rest / 4;
		cout << up << endl;
	}

	return 0;
}