import static java.lang.Math.abs;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        String S=sc.next();
        sc.close();
        int count=0;
        for(int i=0;i<S.length();i++){
            if(S.charAt(i)=='A') count++;
            else count--;
        }
        if(abs(count)==3)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