import java.util.*;
public class Main{
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    // 整数の入力
String S =sc.next();
char a= S.charAt(0);
char b= S.charAt(1);
char c= S.charAt(2);
if(a!=b || b!=c){
  System.out.println("Yes");
}
else{
  System.out.println("No");
}

  }


}

/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