import java.util.*;
public class Main {

		static void solve() {
			Scanner sc = new Scanner(System.in);
			String s = sc.next();
			String res = "Yes";
			if(s.equals("BBB")||s.equals("AAA")) {
				res = "No";
			}
			System.out.println(res);
			sc.close();
		}
	public static void main(String[] args) {
		solve();

	}

}

/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