using System;

class Program
{
    static void Main(string[] args)
    {
        var line = Console.ReadLine();

        string line_1 = line[0].ToString();
        string line_2 = line[1].ToString();
        string line_3 = line[2].ToString();

        Ans(line_1, line_2, line_3);
    }

    static void Ans(string str1, string str2, string str3)
    {
        if(str1 == str2 && str3 != str2)
        {
            Console.WriteLine("Yes");
        }
        else
        {
            Console.WriteLine("No");
        }
    }
}