import java.util.Scanner;
public class Main{
	public static void main(String[] args){
		Scanner scanner = new Scanner(System.in);
		String bus = scanner.next();
		
		if(bus.equals("AAA") || bus.equals("BBB")){
        	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