import java.util.Scanner;

public class Main {
  public static void main(String[] args ) throws Exception {
    Scanner sc = new Scanner(System.in);
    String station = sc.nextLine();
    String station1 = station.substring(0,1);
    String station2 = station.substring(1,2);
    String station3 = station.substring(2, 3);

    if(station1.equals(station2) && station2.equals(station3)) {
    	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