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();
        String[] slist = s.split("");
        int i;
      	if(slist[0].equals("A") && slist[1].equals("A") && slist[2].equals("A")){
        	System.out.println("No");
        }else if(slist[0].equals("B") && slist[1].equals("B") && slist[2].equals("B")){
          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