

import java.util.HashSet;
import java.util.Scanner;


public class Main {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    HashSet<Integer> hs = new HashSet();
    hs.add(sc.nextInt());
    hs.add(sc.nextInt());
    int ans = 0;
    if(!hs.contains(1)) ans = 1;
    else if(!hs.contains(2)) ans = 2;
    else ans = 3;
    System.out.println(ans);
  }

}

/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