import java.util.*;

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

    if (S.equals("AAA") || S.equals("BBB")) {
      System.out.println("No");
      return;
    }
    
    System.out.println("Yes");
    
  }
} import java.util.*; util.* java public class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    String S = sc.next();

    if (S.equals("AAA") || S.equals("BBB")) {
      System.out.println("No");
      return;
    }
    
    System.out.println("Yes");
    
  }
} Main public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    String S = sc.next();

    if (S.equals("AAA") || S.equals("BBB")) {
      System.out.println("No");
      return;
    }
    
    System.out.println("Yes");
    
  } main {
    Scanner sc = new Scanner(System.in);
    String S = sc.next();

    if (S.equals("AAA") || S.equals("BBB")) {
      System.out.println("No");
      return;
    }
    
    System.out.println("Yes");
    
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String S = sc.next(); S sc.next() sc.next sc if (S.equals("AAA") || S.equals("BBB")) {
      System.out.println("No");
      return;
    } S.equals("AAA") || S.equals("BBB") S.equals("AAA") S.equals S "AAA" S.equals("BBB") S.equals S "BBB" {
      System.out.println("No");
      return;
    } System.out.println("No") System.out.println System.out System System.out "No" return; System.out.println("Yes") System.out.println System.out System System.out "Yes" String args[] args public class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    String S = sc.next();

    if (S.equals("AAA") || S.equals("BBB")) {
      System.out.println("No");
      return;
    }
    
    System.out.println("Yes");
    
  }
} public class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    String S = sc.next();

    if (S.equals("AAA") || S.equals("BBB")) {
      System.out.println("No");
      return;
    }
    
    System.out.println("Yes");
    
  }
} Main
import java.util.*;

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

    if (S.equals("AAA") || S.equals("BBB")) {
      System.out.println("No");
      return;
    }
    
    System.out.println("Yes");
    
  }
}