Regex - emails

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Numerics;
using System.Text.RegularExpressions;

namespace C_
{


    class Program
    {
        static void Main(string[] args)
        {
            var input = Console.ReadLine();

            string pattern = @"(^|(?<=\s))([a-zA-Z0-9]+)(\.|-|_)?([a-zA-Z0-9]+)@([a-zA-Z]+.)?([a-zA-Z]+.)?([a-zA-Z0-9]+\.[a-zA-Z]+)";

            MatchCollection matches = Regex.Matches(input, pattern);

            foreach (Match item in matches)
            {
                Console.WriteLine(item.Value);
            }

        }
    }
}