ExtractEmails

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace _01.ExtractEmails
{
    public class StartUp
    {
        public static void Main()
        {
            string emails = Console.ReadLine();
            string pattern = @"([\w.-]+\@[A-Za-z-]+)(\.[a-zA-Z]+)+";
            Regex regex = new Regex(pattern);
            MatchCollection matches = regex.Matches(emails);
            foreach (Match match in matches)
            {
                string result = match.ToString();
                if (!(result.StartsWith("-")||result.StartsWith("_")||result.StartsWith(".")
                   || result.EndsWith("-")||result.EndsWith("_")||result.EndsWith(".")))
                {
                    Console.WriteLine(result);
                }
            }
        }
    }
}