using System;

class Program
{
  Scanner cin;

  void myon()
  {
    cin = new Scanner();

    string S = cin.nextLine();
    for(int i = 0; i < S.Length; i++)
    {
      if(i % 2 == 0)
      {
        if(S[i] == ' ')
        {
          Console.WriteLine("No");
          return;
        }
      } else
      {
        if(S[i] != ' ')
        {
          Console.WriteLine("No");
          return;
        }
      }
    }
    Console.WriteLine("Yes");
  }

  static void Main(string[] args)
  {
    new Program().myon();
  }
}

class Scanner
{
  string[] s;
  int i;
  readonly char[] cs = new char[] { ' ' };

  public Scanner()
  {
    s = new string[0];
    i = 0;
  }

  public string next()
  {
    if (i < s.Length) return s[i++];
    string st = Console.ReadLine();
    while (st == "") st = Console.ReadLine();
    s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
    if (s.Length == 0) return next();
    i = 0;
    return s[i++];
  }

  public string nextLine()
  {
    return Console.ReadLine();
  }

  public int nextInt()
  {
    return int.Parse(next());
  }

  public long nextLong()
  {
    return long.Parse(next());
  }

  public double nextDouble()
  {
    return double.Parse(next());
  }
}