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

namespace _14.Letters_Change_Numbers
{
    public class LettersChangeNums
    {
        public static void Main()
        {
            string[] line = Console.ReadLine()
                .Split(new[] {' ', '\t', '\n', '\r'}, StringSplitOptions.RemoveEmptyEntries);
            int position = 0;
            decimal sum = 0M;
            decimal total = 0M;


            foreach (var str in line)
            {
                char firstLetter = str[0];
                char secondLetter = str[str.Length - 1];
                decimal num = decimal.Parse(str.Substring(1, str.Length - 2));

                if (Char.IsUpper(firstLetter))
                {
                    position = (int)firstLetter - (int)'A' + 1;
                    sum = num / position;
                }
                if (Char.IsLower(firstLetter))
                {
                    position = (int)firstLetter - (int)'a' + 1;
                    sum = num * position;
                }
                if(Char.IsUpper(secondLetter))
                {
                    position = (int)secondLetter - (int)'A' + 1;
                    sum -= position;
                }
                if (Char.IsLower(secondLetter))
                {
                    position = (int)secondLetter - (int)'a' + 1;
                    sum += position;
                }

                total += sum;
                sum = 0;
            }

            Console.WriteLine("{0:f2}", total);
        }
    }
}