import java.util.*;

import javax.lang.model.util.ElementScanner6;
/**
 * test
 */
public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        String s = sc.next();
        if (s.equals("AAA")){
            System.out.println("No");
        } else if(s.equals("BBB")){
            System.out.println("No");
        } else {
            System.out.println("Yes");
        }
}
}

/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