using System;

public class Program

{

    public static void Main()

    {

        string text = "SQLDataABCHumaAdADScVascASCasASCasASCTumEKa";

        var formatted = String.Empty;

        int i = 0;

        var totalLeangth = text.Length;

        foreach (char letter in text)

        {

​

            if (Char.IsUpper(letter) && i < totalLeangth - 1)

            {

                if (char.IsLower(text[i + 1]) && char.IsLower(text[i - 1]))

                    formatted += letter;

​

                else if (char.IsLower(text[i + 1]))

                    formatted += " " + letter;

​

                else

                    formatted += letter;

            }

            else if (i == totalLeangth - 1)

            {

                if (Char.IsUpper(letter) && char.IsUpper(text[i - 1]))

                {

                    formatted += letter;

                }

                else if(Char.IsUpper(text[i-1]))

                {

                    formatted += letter;

                }

                else

                {

                    formatted += " " + letter;

                }

            }

            else if (Char.IsLower(letter) && char.IsUpper(text[i + 1]))

            {

                formatted += letter + " ";

            }

            else

            {

                formatted += letter;

            }

            i = i + 1;

        }

        Console.WriteLine(formatted);

        Console.ReadLine();

    }

}