


import java.util.*;
	public class Main {
	public static void main(String[] args) {
		
		
			Scanner sc=new Scanner(System.in);
			//there's only 1 2 and 3
			// sum = 6;
			int a=sc.nextInt();
			int b=sc.nextInt(); 
			
			
			int sum=a+b;
			
			System.out.println(6-sum);
}
	
	}
/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