import java.util.*;
 
public class Main {
  
  public static void main(String[] args){
  Scanner s=new Scanner(System.in);
  String S=s.next();
  
  if(S.equals("AAA") || S.equals("BBB")){
    System.out.print("No");
  }else{
    System.out.print("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