using System;

using System.Globalization; 

​

public class Program

{

        private static readonly string[] DateFormats =

        {

            "d",

            "t",

            "T",

            "yyyy",

            "M.yyyy",

            "d.M.yyyy",

            "d.M.yyyy HH:mm",

            "d.M.yyyy HH:mm:ss",

            "d.M.yyyy HH.mm",

            "d.M.yyyy HH.mm.ss",

            "d/M/yyyy HH:mm:ss",

            "d/M/yyyy HH.mm.ss",

            "d.M.yy",

            "HH:mm",

            "HH:mm:ss",

            "HH.mm",

            "HH.mm.ss",

            "o",

            "s",

            "MMMM yyyy",

            "MMM yyyy",

            "MM.yyyy",

            "yyyy-MM-dd",

            "yyyy-MM-dd HH:mm",

            "yyyy-MM-dd HH:mm:ss"

        };

    public static void Main()

    {

        DateTime result;

        if (DateTime.TryParseExact("2020-06-27T22:50:05.977", DateFormats, CultureInfo.CurrentCulture, DateTimeStyles.AllowWhiteSpaces, out result))

        {

            Console.WriteLine(result);

        }

        else

        {

            Console.WriteLine("Unknown date format");

        }

    }

}