using System;
using static System.Console;
namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var N = ReadLine();
            for(int i = 0; i < N.Length; i++)
            {
                if(i % 2 == 0)
                {
                    if(N[i] == ' ')
                    {
                        WriteLine("No");
                        return;
                    }
                }
                else
                {
                    if (N[i] != ' ')
                    {
                        WriteLine("No");
                        return;
                    }
                }
            }
            WriteLine("Yes");
        }
    }
}