08. Letters Change Numbers

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

namespace LettersChangeNumbers
{

    class Program
    {
        static void Main()
        {
            string[] tokens = Console.ReadLine().Split(" ", StringSplitOptions.RemoveEmptyEntries);
            double totalSum = 0;

            for (int i = 0; i < tokens.Length; i++)
            {
                char firstLetter = tokens[i][0];
                char secondLetter = tokens[i][^1];
                double number = int.Parse(tokens[i].Substring(1, tokens[i].Length - 2));

                _ = char.IsUpper(firstLetter) ? number /= firstLetter - 64 : number *= firstLetter - 96;
                _ = char.IsUpper(secondLetter) ? number -= secondLetter - 64 : number += secondLetter - 96;

                totalSum += number;
            }

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