import java.util.Scanner;
import java.util.Arrays;
class Main{
public static void main(String[] args){
 Scanner scan = new Scanner(System.in);
 
 String S = scan.next();
 String[] split = S.split("");
  
   if (split[0].equals(split[1]) && split[1].equals(split[2]))
 	 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