import java.util.*;

public class Main{
  
  public static void main(String[] args){
	Scanner scanner = new Scanner(System.in);
	  int[] ans = {1,2,3};
	  int wAns1 = scanner.nextInt();
	  int wAns2 = scanner.nextInt();
	  scanner.close();
	  for (int i : ans) {
		if (i != wAns1 && i != wAns2) {
			System.out.println(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