import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
	    int A = scanner.nextInt();
	    int B = scanner.nextInt();
	    int[] answers = {1, 2, 3};
	    
	    for (int answer : answers) {
	    	if (A == answer) {
	    		continue;
	    	} else if (B == answer) {
	    		continue;
	    	} 
            System.out.println(answer);
	    }
	}	
}	
/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