import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {

        Scanner scan = new Scanner(System.in);
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
        
        boolean[] ans = new boolean[4];
        
        ans[scan.nextInt()] = true;
        ans[scan.nextInt()] = true;
        
        for(int i = 1; i <4; i++){
            if(!ans[i]){
                out.println(i);
            }
        }
        out.close();
        
    }
}
/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