import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.util.stream.Collectors;

public class Main {

    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        // int N = Integer.parseInt(s.next());
        String S = s.next();
        List<String> ret = Arrays.asList(S.split("")).stream().distinct().collect(Collectors.toList());
        System.out.println(ret.size() == 1 ? "No" : "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