#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <set>
using namespace std;


int main(){
	int n;
	cin >> n;
	vector<int> v(10, 0);
	for(int i=0; i<n; i++){
		int a,b,c;
		cin >> a >> b >> c;
		a--;b--;c--;
		v[a]++;
		v[b]++;
		v[c]++;
	}

	int ans = 0;
	int rem = 0;
	for(int i=0; i<10; i++){
		ans += v[i]/2;
		rem += v[i]%2;
	}
	ans += rem/4;

	cout << ans << endl;
	return 0;
}