using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(IsValidEmail("-}$!~{ac=co^'un*&t-i+ng~!^$%a@grissellsworth.com")+"");

        Console.WriteLine(IsValidEmail("roshan+maharjan{roshan}{maharjan}@gr--is-se_lls.wo-rth.mobile")+"");

        Console.WriteLine(IsValidEmail("!accounting@worth.com")+"");

        Console.WriteLine(IsValidEmail("\"roshan.maharjan\"@gmail.com")+"");

        Console.WriteLine(IsValidEmail("accounting@localserver")+"");

        Console.WriteLine(IsValidEmail("\"roshan@nyc\"_ny@gmail.com")+"");

    }

    public static  bool IsValidEmail(string a_email)

        {

           string v_pattern = "^([-a-zA-Z0-9~!$%^&*_=+}{\\'?]+(\\.[-a-zA-Z0-9~!$%^&*_=+}{\\'?]+)*@([0-9a-zA-Z][-\\w]*[0-9a-zA-Z]\\.)+[a-zA-Z]{2,9})$";

        ///^[-a-z0-9~!$%^&*_=+}{\'?]+(\.[-a-z0-9~!$%^&*_=+}{\'?]+)*@([a-z0-9_][-a-z0-9_]*(\.[-a-z0-9_]+)*\.(aero|arpa|biz|com|coop|edu|gov|info|int|mil|museum|name|net|org|pro|travel|mobi|[a-z][a-z])|([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}))(:[0-9]{1,5})?$/i

            if (Regex.IsMatch(a_email, v_pattern))

            {

                return true;

            }

            else

            {

                return false;

            }

        }

}