using System;

public class Program

{

    public static string ToCamelCase(string s)

    {

        if (string.IsNullOrEmpty(s))

            return s;

​

        char[] chars = s.ToCharArray();

        var intStart = 0;

        var isStart = true;

​

        for (int i = 0; i < chars.Length; i++)

        {

            bool hasNext = (i + 1 < chars.Length);

            if (i > intStart && hasNext && !char.IsUpper(chars[i + 1]))

            {

                if (char.IsSeparator(chars[i + 1]))

                {

                    chars[i] = char.ToLowerInvariant(chars[i]);

                }

                isStart = false;

            }

            if (isStart)

            {

                chars[i] = char.ToLowerInvariant(chars[i]);

            }

            if (chars[i] == '.') {

                isStart = true;

                intStart = i + 1;

            }

        }

​

        return new string(chars);

    }

    public static void Main()

    {

        Console.WriteLine(ToCamelCase("VBNCode.Test"));

        Console.WriteLine(ToCamelCase("ArticleSort.VBNCode"));

        Console.WriteLine(ToCamelCase("ArticleGroupConverter.VBNCode"));

        Console.WriteLine(ToCamelCase("MyName.IsHaas"));

    }

}