using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using static System.Console;
using static System.Math;

class Program
{
    static void Main()
    {
        var r =ReadLine();
        var a=true;
        for (int i = 0; i < r.Length; i++)
        {
            if(i%2==1&&r[i]!=' ')a=false;
            if(i%2==0&&r[i]==' ')a=false;
        }
        WriteLine(a?"Yes":"No");
    }
}