using System;

using System.Linq;

using System.Globalization;

​

using System.Threading;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(DateTime.Parse("12/08/2017",new CultureInfo("pl-PL") ).Day);

        var cc = Thread.CurrentThread.CurrentCulture;

        var cuic = Thread.CurrentThread.CurrentUICulture;

        Console.WriteLine(cc.ToString());

        Console.WriteLine(cuic.ToString());

    }

}