#include<iostream>
#include<string>
#include<string.h>
#include<algorithm>
#include<stdio.h>
#include<cmath>
#include<vector>
#include<utility>
#include<stack>
#include<queue>
#include<list>
#include<bitset>

#define FOR(i, a, b) for(int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for(int i=(a);i>=(b);i--)
#define MOD 1000000007
#define INF 1000000000

using namespace std;


int main(void) {
	int n;
	int dp[11] = {};
	int count = 0;
	int total = 0;

	cin >> n;
	FOR(i, 1, n) {
		int a, b, c;
		cin >> a >> b >> c;
		dp[a]++;
		dp[b]++;
		dp[c]++;

	}
	FOR(i, 1, n) {
		while (dp[i] >= 2) {
			count++;
			dp[i] -= 2;
		}
	}
	FOR(i, 1, n) {
		total += dp[i];
	}
	count += total / 4;
	cout << count << endl;
	return 0;
}