#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
using namespace std;

int mmax(int a, int b) {
	int x = (a > b) ? a : b;
	return x;
}

int mmin(int a, int b) {
	int x = (a < b) ? a : b;
	return x;
}

int main() {
	int n;
	cin >> n;

	int count[10] = {0};
	for (int i = 0; i < n; i++) {
		int a, b, c;
		cin >> a >> b >> c;
		a--; b--; c--;
		count[a]++; count[b]++; count[c]++;
	}
	int amari = 0,ans=0;
	for (int i = 0; i < 10; i++) {
		amari += count[i] % 2;
		ans += count[i] / 2;
	}

	cout << ans + amari / 4 << endl;
	return 0;
}