#include <bits/stdc++.h>
using namespace std;

int main(){
	int n;
	cin >> n;
	vector<int> items(10,0);
	while(n--){
		for(int i=0;i<3;i++){
			int a;
			cin >> a;
			items[a-1]++;
		}
	}
	int power_up=0;
	int residue=0;
	for(int i=0;i<10;i++){
		power_up+=items[i]/2;
		residue+=items[i]%2;
	}
	power_up+=residue/4;
	cout << power_up << endl;
	return 0;
}