import java.util.*;
class Main {
	public static void main(String[] args) throws Exception {
		final Scanner sc = new Scanner(System.in);

        String s = sc.next();
        sc.close();
        char t = s.charAt(0);

        for (int i = 1; i < 3; i++) {
            if(t != s.charAt(i)){
                System.out.println("Yes");
                return;
            }
        }
        System.out.println("No");
    }

}

/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