import java.util.*;
import java.lang.Math;

public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

  		
      	String sta = sc.next();
      	String str = "Yes";
      	
      	if(sta.equals("AAA") || sta.equals("BBB")) str = "No";
      	
      	
      	System.out.println(str);
        
	}
}

/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