import java.util.Scanner;

class Main {
	public static void main(String[] args) {

	    Scanner sc = new Scanner(System.in);
	    String S = sc.next();
	    char[] s = new char[3];

	    for (int i = 0; i < 3; i++) {
	    	s[i] = S.charAt(i);
	    }

	    if (s[0] == s[1] && s[0] == s[2]) {
	    	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