using System;

using System.Linq;

using System.Text.RegularExpressions;

​

public class Program

{

    static string CamelCaseToSpaceSeparated(string text) 

    {

        string[] words = Regex.Matches(text, @"([A-Z]+(?![a-z])|[A-Z][a-z]+|[0-9]+|[a-z]+)")

            .OfType<Match>()

            .Select(m => m.Value)

            .ToArray();

        return string.Join(" ", words);

    }

    public static void Main()

    {

        Console.WriteLine(CamelCaseToSpaceSeparated("MyHTTPServer"));

        Console.WriteLine(CamelCaseToSpaceSeparated("XMLReaderFactory"));

        Console.WriteLine(CamelCaseToSpaceSeparated("_myNewUIControl"));

        Console.WriteLine(CamelCaseToSpaceSeparated("readInt32_silent"));

        Console.WriteLine(CamelCaseToSpaceSeparated("_12DaysLater"));

        Console.WriteLine(CamelCaseToSpaceSeparated("IMG_ButtonIcon_16px"));

        Console.WriteLine(CamelCaseToSpaceSeparated("PrintButton_MouseOver"));

        Console.WriteLine(CamelCaseToSpaceSeparated("int32_45_78Stuff"));

    }

}