using System;

using System.Globalization;

public class Program

{

    public static void Main()

    {

        var dt = DateTime.Now;

        if (DateTime.TryParseExact("2015-05-13 11:28:23", "yyyy-MM-dd HH:mm:ss", null, DateTimeStyles.None, out dt))

        {

            Console.WriteLine("Hello World");

        }

    }

}