import java.util.Scanner;

public class Main {
    public static void main(String args[]) {
        Scanner scanner = new Scanner(System.in);
        char[] chars = scanner.next().toCharArray();
        scanner.close();
        if (chars[0] == chars[1] && chars[1] != chars[2]) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
}