using System;

using System.Text;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var inputs = new []{"a1", "a2", "a3", "a4", "a5", "a6", "a7", "a8", "a9", "a10", "a11"};

        Console.WriteLine("Default Sorting:");

        foreach(var x in inputs.OrderBy(y => y)){

            Console.WriteLine(x);

        }

        Console.WriteLine("           ");

        Console.WriteLine("-----------");

        Console.WriteLine("           ");

        Console.WriteLine("Crazy Sorting:");

        foreach(var x in inputs.OrderBy(y => Naturalize(y))){

            Console.WriteLine(x);

        }

    }

    public static string Naturalize(string str)

    {

        if (string.IsNullOrEmpty(str))

            return str;

​

        const int maxLength = 450;

        const int padLength = 15;

​

        bool isDecimal = false;

        bool wasSpace = false;

        int numStart = 0;

        int numLength = 0;

​

        var sb = new StringBuilder();

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

        {

            char c = str[i];

            if (c >= '0' && c <= '9')

            {

                if (numLength == 0)

                    numStart = i;

                numLength++;

            }

            else

            {

                if (numLength > 0)

                {

                    sb.Append(pad(str.Substring(numStart, numLength), isDecimal, padLength));

                    numLength = 0;

                }

                if (c != ' ' || !wasSpace)

                    sb.Append(c);

                isDecimal = c == '.';

                if (sb.Length > maxLength)

                    break;

            }

            wasSpace = c == ' ';

        }

        if (numLength > 0)

            sb.Append(pad(str.Substring(numStart, numLength), isDecimal, padLength));

​

        if (sb.Length > maxLength)

            sb.Length = maxLength;

        return sb.ToString();

    }

​

    private static string pad(string num, bool isDecimal, int padLength)

    {

        return isDecimal ? num.PadRight(padLength, '0') : num.PadLeft(padLength, '0');

    }

}