
import java.util.*;
import java.io.*;

import static java.lang.Character.isUpperCase;

public class Main {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        int A = in.nextInt();
        int B = in.nextInt();
        if(A==1 && B==2 || A==2 && B==1)
        {
            System.out.println(3);
        }
        else if(A==2 && B==3 || A==3 && B==2)
        {
            System.out.println(1);
        }
        else if(A==1 && B==3 || A==3 && B==1)
        {
            System.out.println(2);
        }
        else
            {
                System.out.println("ERROR");
            }







        }







    }















/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