#include <iostream>
#include <sstream>
#include <math.h>
#include <stack>
#include <set>
#include <algorithm>
#include <string>
#include <queue>
#include <stack>
#include <map>
#include <cstdio>
#include <vector>
using namespace std;

#define INF (1 << 30)
#define INFLL (1LL << 60)

int main() {
	int n;
	int a,b,c;
	int how[12] = {};
	cin >> n;
	for(int i = 0;i < n;i++){
		cin >> a >> b >> c;
		how[a]++;
		how[b]++;
		how[c]++;
	}
	int ans = 0;
	int amari = 0;
	for(int i = 1;i < 11;i++){
		ans += how[i] / 2;
		amari += how[i] % 2;
	}
	ans += amari / 4;
	cout << ans << endl;
	return 0;
}