import java.util.*;

public class Main {
    public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		String str = scan.nextLine();
		if(str.charAt(0) == str.charAt(1) && str.charAt(0) != str.charAt(2)){
			System.out.println("Yes");
		}else{
			System.out.println("No");
		}
    }
}