import java.util.Scanner;

class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    String sa = sc.nextLine();
    char[] s = sa.toCharArray();
    Boolean f = (s[0] != s[1] || s[0] != s[2] || s[1] != s[2]);
    if(f) {
      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