#include<iostream>
#include<algorithm>
using namespace std;
int main(void){
	int N,res = 0,p;
	int item[11] = { 0 };
	cin >> N;
	while (N--){
		cin >> p; item[p]++;
		cin >> p; item[p]++;
		cin >> p; item[p]++;
	}
	p = 0;
	for (int i = 1; i < 11; i++){
		res += item[i]>>1; p += item[i] & 1;
	}
	res += p / 4;
	cout << res << endl;
	return 0;
}