import java.util.Scanner;

public class Main {
  	public static void main(String[] args){
      //入力値の取得
      Scanner sc = new Scanner(System.in);
      String str = sc.next();
      sc.close();

      if (str.indexOf("A") == -1 || str.indexOf("B") == -1) {
    	  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