Number as Words

using System;

class NumberAsWords
{
    static void Main()
    {
        while (true)
        {
            int input = int.Parse(Console.ReadLine());
            int spec = 0;
            if (((input / 100) % 10 >= 1) && ((input / 100) % 10 <= 9))
            {
                int firstDigit = (input / 100) % 10;
                switch (firstDigit)
                {
                    case 1:
                        Console.Write("one hundred ");
                        break;
                    case 2:
                        Console.Write("two hundred ");
                        break;
                    case 3:
                        Console.Write("three hundred ");
                        break;
                    case 4:
                        Console.Write("four hundred ");
                        break;
                    case 5:
                        Console.Write("fife hundred ");
                        break;
                    case 6:
                        Console.Write("six hundred ");
                        break;
                    case 7:
                        Console.Write("seven hundred ");
                        break;
                    case 8:
                        Console.Write("eight hundred ");
                        break;
                    case 9:
                        Console.Write("nine hundred ");
                        break;
                }
                if ((input % 10 != 0) || ((input % 100) <= 90) && (input % 100) >= 10)
                {
                    int and = 1;
                        switch (and)
                        {
                            case 1 :
                                Console.Write("and ");
                                break;
                        }
                }
            }
            if (((input / 10) % 10 >= 0) && ((input / 10) % 10 <= 9))
            {
                if ((input % 10 == 0) && (input != 0))
                {
                    spec++;
                }
                int secondDigit = (input / 10) % 10;
                switch (secondDigit)
                {
                    case 1:
                        int special = input % 100;
                        spec++;
                        switch (special)
                        {
                            case 10:
                                Console.WriteLine("ten");
                                break;
                            case 11:
                                Console.WriteLine("eleven");
                                break;
                            case 12:
                                Console.WriteLine("twelve");
                                break;
                            case 13:
                                Console.WriteLine("thirteen");
                                break;
                            case 14:
                                Console.WriteLine("fourteen");
                                break;
                            case 15:
                                Console.WriteLine("fiveteen");
                                break;
                            case 16:
                                Console.WriteLine("sixteen");
                                break;
                            case 17:
                                Console.WriteLine("seventeen");
                                break;
                            case 18:
                                Console.WriteLine("eighteen");
                                break;
                            case 19:
                                Console.WriteLine("nineteen");
                                break;
                        }
                        break;
                    case 2:
                        Console.Write("twenty ");
                        break;
                    case 3:
                        Console.Write("thirty ");
                        break;
                    case 4:
                        Console.Write("forty ");
                        break;
                    case 5:
                        Console.Write("fifty ");
                        break;
                    case 6:
                        Console.Write("sixty ");
                        break;
                    case 7:
                        Console.Write("seventy ");
                        break;
                    case 8:
                        Console.Write("eighty ");
                        break;
                    case 9:
                        Console.Write("ninety ");
                        break;
                }
            }
            if ((input % 10 >= 0) && (input % 10 <= 9) && (spec == 0))
            {
                int inputLastDigit = input % 10;
                switch (inputLastDigit)
                {
                    case 0:
                        Console.Write("zero");
                        break;
                    case 1:
                        Console.Write("one");
                        break;
                    case 2:
                        Console.Write("two");
                        break;
                    case 3:
                        Console.Write("three");
                        break;
                    case 4:
                        Console.Write("four");
                        break;
                    case 5:
                        Console.Write("fife");
                        break;
                    case 6:
                        Console.Write("six");
                        break;
                    case 7:
                        Console.Write("seven");
                        break;
                    case 8:
                        Console.Write("eight");
                        break;
                    case 9:
                        Console.Write("nine");
                        break;
                }
            }
            Console.WriteLine("");
        }
    }
}