using System;

using System.Text.RegularExpressions;

public class Program

{

    public static string ToUserDisplay(string originalString)

        {

            string[] split = Regex.Split(originalString, @"(?<!^)(?=[A-Z])");

            for (var i = 0; i < split.Length; i++)

            {

                var str = split[i];

                if (!string.IsNullOrEmpty(str))

                    split[i] = string.Format("{0}{1}", char.ToUpper(str[0]), str.Substring(1));//"{char.ToUpper(str[0])}{str.Substring(1)}";

            }

            return string.Join(" ", split);

        }

    public static void Main()

    {

        Console.WriteLine("Hello World");   

        Console.WriteLine(ToUserDisplay("HelloWorld"));     

        Console.WriteLine(ToUserDisplay("IRR"));

        Console.WriteLine(ToUserDisplay("NPV"));

        Console.WriteLine(ToUserDisplay("NPVAssetValue"));

        Console.WriteLine(ToUserDisplay("URL"));

    }

}