import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] x = new int[11];
		for(int i = 0 ; i < n ; i++) {
			int a = sc.nextInt();
			int b = sc.nextInt();
			int c = sc.nextInt();
			x[a]++; x[b]++; x[c]++;
		}
		int ans = 0; int cnt = 0;
		for(int i = 0 ; i < 11 ; i++) {
			ans += x[i] / 2;
			cnt += x[i] % 2;
		}
		ans += cnt / 4;
		System.out.println(ans);
 	}
}