import java.util.Scanner;

public class Main {

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