import java.util.Scanner;
public class Main {
    public static void main (String...args) {
        Scanner sc = new Scanner(System.in); String S = sc.next(); char[] ch = S.toCharArray();
        System.out.println(ch[0] != ch[1] || ch[1] != ch[2] ? "Yes" : "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