using System.Numerics;

public class Program
{
    public static void Main()
    {
        //Biginteger num =BigInteger.Parse(Console.ReadLine() ?? string.Empty);
        //string[] str = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        string str = Console.ReadLine() ?? string.Empty;



        for(int i = 0; i < str.Length; i++)
        {
            if(i % 2 != 0 && str[i] != ' ' || i % 2 == 0 && !Char.IsLower(str[i]))
            {
                Console.WriteLine("No");
                return;
            }
        }
        Console.WriteLine("Yes");
    }
}