import java.util.Scanner;

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