import java.util.*;

public class Main {
    public static void main(String[] args) {
        int [] answers = {1,2,3};
        Scanner s = new Scanner(System.in);
        int a = s.nextInt();
        int b = s.nextInt();
        for(int i = 0; i<answers.length; i++){
            if(answers[i] != a && answers[i] != b){
                System.out.println(answers[i]);
            }
        }
    }
}

/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