Decoding Exam Tsak

using System;
class Program
{
    static void Main()
    {
        int salt = int.Parse(Console.ReadLine());
        string text = Console.ReadLine();
        int position = 0;

        foreach (char symbol in text)
        {
            if (symbol == '@')
            {
                break;
            }

            else if (symbol >= 'A' && symbol <= 'z')
            {
                int letter = Convert.ToInt32(symbol);
                int letterSum = (letter * salt) + 1000;

                double finalSumLetter = 0;

                position++;
                if (position % 2 == 0)
                {
                    finalSumLetter = letterSum * 100;
                    Console.WriteLine(finalSumLetter);
                }
                else
                {
                    finalSumLetter = letterSum / 100.00;
                    Console.WriteLine("{0:F2}", finalSumLetter);
                }

            }

            else if (symbol == '0' || symbol == '1' || symbol == '2' || symbol == '3' || symbol == '4' || symbol == '5' || symbol == '6' || symbol == '7' || symbol == '8' || symbol == '9')
            {
                int currentNumber = symbol + salt + 500;
                double finalSumNumber = 0;

                position++;
                if (position % 2 == 0)
                {
                    finalSumNumber = currentNumber * 100;
                    Console.WriteLine(finalSumNumber);
                }

                else
                {
                    finalSumNumber = currentNumber / 100.00;
                    Console.WriteLine("{0:F2}", finalSumNumber);
                }
            }

            else
            {
                int anyOtherSymbol = (Convert.ToInt32(symbol) - salt);
                double sumAnyOtherSymbol = 0;

                position++;
                if (position % 2 == 0)
                {
                    sumAnyOtherSymbol = anyOtherSymbol * 100;
                    Console.WriteLine(sumAnyOtherSymbol);
                }

                else
                {
                    sumAnyOtherSymbol = anyOtherSymbol / 100.00;
                    Console.WriteLine("{0:F2}", sumAnyOtherSymbol);
                }
            }

        }
    }

}