using System;
using System.Linq;
using System.Collections.Generic;
using System.IO;

class MyClass
{
    public static void Solve()
    {
        var S = Console.ReadLine();
        for (int i = 0; i < S.Length; i++)
        {
            if (i % 2 == 0 && S[i] == ' ')
            {
                Console.WriteLine("No");
                return;
            }
            if (i % 2 == 1 && S[i] != ' ')
            {
                Console.WriteLine("No");
                return;
            }
        }
        Console.WriteLine("Yes");
    }

    public static void Main()
    {
        var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
        Console.SetOut(sw);
        Solve();
        Console.Out.Flush();
    }
}