import java.util.Arrays;
import java.util.Iterator;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);

		int N = in.nextInt();
		int num[] = new int[10];
		Arrays.fill(num, 0);
		for (int i = 0; i < N; i++) {
			int a, b, c;
			a = in.nextInt();
			b = in.nextInt();
			c = in.nextInt();
			num[a - 1]++;
			num[b - 1]++;
			num[c - 1]++;
		}
		int ans = 0;
		for (int i = 0; i < 10; i++) {
			ans += num[i] / 2;
			num[i] = num[i] % 2;
		}
		int amari = 0;
		for (int i = 0; i < 10; i++) {
			if (num[i] != 0) {
				amari++;
			}
		}
		ans += amari / 4;
		System.out.println(ans);
	}
}