using System;

using System.Globalization;

public class Program

{

    public static void Main()

    {

        String time = "20170620 21:22:02 EST";

        Console.WriteLine(DateTime.ParseExact(time.Replace("EST", "-05:00"), "yyyyMMdd HH:mm:ss zzz", CultureInfo.InvariantCulture));

    }

}