import java.util.*;
import java.util.ArrayList;

class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int b = sc.nextInt();

    ArrayList<Integer> c = new ArrayList<Integer>();
    c.add(1);
    c.add(2);
    c.add(3);

    c.remove(c.indexOf(a));
    c.remove(c.indexOf(b));
    System.out.println(c.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