#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <map>
#include <list>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <queue>
#include <iomanip>
#define INF 1050000000

using namespace std;

int main(void)
{
	int n;
	int a, b, c;
	int x[11];
	int ans = 0;
	int cnt = 0;

	memset(x, 0, sizeof(x));

	cin >> n;

	for (int i = 0; i < n; i++) {
		cin >> a >> b >> c;
		x[a]++;
		x[b]++;
		x[c]++;
	}
	for (int i = 1; i <= 10; i++) {
		ans += x[i] / 2;
		if (x[i] % 2 == 1) cnt++;
	}
	ans += cnt / 4;

	cout << ans << endl;
}