емайл доделать

using System;
using System.Text;
using System.Text.RegularExpressions;

class MainClass
{
   public static void Main (string[] args)
  {
    string all_domen = @"(([-A-Za-z0-9]{1,63}\.)+[a-z]{2,4})";
    string mailbox = $@"\w+";
    string pattern = $@"{mailbox}@{all_domen}";

    string str;

    while((str = Console.ReadLine())!= null)
      foreach (Match match in Regex.Matches(str, pattern))
         Console.WriteLine(match.Value);
  }
}