using System;

public class Hello
{
    static void Main()
    {
        var s = Console.ReadLine().Trim();
        Console.WriteLine(check(s) ? "Yes" : "No");
    }
    static bool check(string s)
    {
        for (int i = 0; i < s.Length; i++)
            if ((i % 2 == 0 && s[i] == ' ') |
            (i % 2 == 1 && s[i] != ' ')) return false;
        return true;
    }
}