import java.util.*;

public class Main {
public static void main(String[] args) {
	
	Scanner sc = new Scanner(System.in);
		
 	String str  = sc.next();
  
  	char[] c_arr = str.toCharArray();
    
    sc.close();
  	
    if (c_arr[0] == 'A' && c_arr[1] == 'A' && c_arr[2] == 'A') {
         System.out.print("No"); 
    } else if (c_arr[0] == 'B' && c_arr[1] == 'B' && c_arr[2] == 'B') {
         System.out.print("No"); 
    } else {
         System.out.print("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