import java.util.*;

class Main{
 public static void main(String args[]){
   Scanner scn = new Scanner(System.in);
   String a = scn.nextLine();
   String b = scn.nextLine();
   List<String> li = new ArrayList<String>();
   li.add("1");
   li.add("2");
   li.add("3");
   li.remove(a);
   li.remove(b);
   System.out.println(Integer.parseInt(li.get(0)));
 }
}
/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