#include<iostream>
using namespace std;
int main(void){
	int v[11] = { 0 };
	int n; cin >> n;
	for (int i = 0; i < n; i++){
		int a, b, c; cin >> a >> b >> c;
		v[a]++; v[b]++; v[c]++;
	}
	int ans = 0, tmp = 0;
	for (int i = 0; i < 11; i++){
		ans += v[i] / 2;
		tmp += v[i] % 2;
	}
	cout << ans + tmp / 4 << endl;
	return 0;
}