#include "bits/stdc++.h"
using namespace std;
#define MAX 11

int dp[MAX];
int main() {
	int N;
	cin >> N;
	for (int i = 0; i < N; i++)
	{
		int a, b, c;
		cin >> a >> b >> c;
		dp[a]++; dp[b]++; dp[c]++;
	}
	int ans = 0;
	int temp = 0;
	for (int i = 0; i < MAX; i++)
	{
		ans += dp[i] / 2;
		temp += dp[i] % 2;
	}
	ans += temp / 4;
	cout << ans << endl;
}