String - null or empty

using System;

namespace StringTheException
{
  class Program
  {
    static void Main(string[] args)
    {
     Console.Write("Please enter a number or word.");
     string msg = Console.ReadLine();

     if (msg == null || String.IsNullOrEmpty(msg) ){    //to check if string is null or empty
       Console.WriteLine("You didn't enter anything!");
     }
     else{
       Console.WriteLine("Thank you for your submission!");
     }

    }
  }
}