LettersChangeNumbers

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace LettersChangeNumbersSecondTry
{
    public  class LettersChangeNumbersSecondTry
    {
        public static void Main()
        {
            string[] inputLine = Console.ReadLine().Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);

            decimal totalSum = 0.0m;
            for (int currCombination = 0; currCombination < inputLine.Length; currCombination++)
            {
                string combination = inputLine[currCombination];

                StringBuilder numberToParse = new StringBuilder();
                for (int currNum = 1; currNum < combination.Length - 1; currNum++)
                {
                    numberToParse.Append(combination[currNum]);
                }

                char firstLetter = combination[0];
                char lastLetter = combination[combination.Length - 1];
                decimal number = decimal.Parse(numberToParse.ToString());

                decimal currSum = 0.0m;

                if (char.IsUpper(firstLetter))
                {
                    currSum = number / (firstLetter - 'A' + 1);
                }
                else
                {
                    currSum = number * (firstLetter - 'a' + 1);
                }

                if (char.IsUpper(lastLetter))
                {
                    currSum -= (lastLetter - 'A' + 1);
                }
                else
                {
                    currSum += (lastLetter - 'a' + 1);
                }

                totalSum += currSum;
            }

            Console.WriteLine($"{totalSum:f2}");
        }
    }
}