import java.util.*;

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