import java.util.Scanner;

public class Main{
	public static void main(String args[]){
		Scanner sc = new Scanner(System.in);
		String s1 = sc.nextLine();
        String s2 = sc.nextLine();
        int a = Integer.parseInt(s1);
        int b = Integer.parseInt(s2);
        int c = 6;
        System.out.println(c - a - b);
	}
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz