using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Text;
using static System.Console;
using static System.Math;

namespace CP
{
    class Atria
    {
        static void Main(string[] args)
        {
            string s = ReadLine();
            for (int i = 0; i < s.Length; i++)
            {
                if (i % 2 == 1)
                {
                    if (s[i] != ' ')
                    {
                        WriteLine("No");
                        return;
                    }
                }
                else if (char.IsUpper(s[i]) && s[i] != ' ')
                {
                    WriteLine("No");
                    return;
                }
            }
            WriteLine("Yes");
        }

    }
}