import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Integer[] choices = { 1, 2, 3 };
        Scanner sc = new Scanner(System.in);

        Integer A = sc.nextInt();
        Integer B = sc.nextInt();

        for (Integer choice : choices) {
            if (choice != A && choice != B) {
                System.out.println(choice);
                break;
            }
        }

        sc.close();

    }

}
/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