using System;

class Program
{
    static void Main(string[] args)
    {
        var N = Console.ReadLine();
        try
        {
            int.Parse(N);
        }
        catch (Exception)
        {
            Console.WriteLine("No");
        }
        if (N.Length == 2) Console.WriteLine("Yes");
        else Console.WriteLine("No");
    }
}