Encoding Nums

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

namespace EncodingSum
{
    class Program
    {
        static void Main()
        {
            /* @ means end of input and printing result
             * digits 0-9 multiply the result by the value of the digit
             * letters - index is added to the result (note. alphabet starts with a 0 and ends in 25)
             * a "default" symbol means "moduling" the result (%)
             */

            double result = 0;

            double M = double.Parse(Console.ReadLine());
            string text = Console.ReadLine();

            foreach (char symbol in text)
            {
                if ((symbol >= 'A' && symbol <= 'Z') ||( symbol >= 'a' && symbol <= 'z'))
                {
                    if (symbol >= 'A' && symbol <= 'Z')
                    {
                        result += symbol - 65;
                    }
                    if (symbol >= 'a' && symbol <= 'z')
                    {
                        result += symbol - 97;
                    }

                }
                else if (symbol >= '0' && symbol <= '9')
                {
                    int currentNumber = symbol - '0';
                    result *= currentNumber;
                }
                else if ((symbol >= 0 && symbol <= 47) || (symbol >= 58 && symbol <= 63) || (symbol >= 91 && symbol <= 96) || (symbol >= 123 && symbol <= 255))
                {
                    result = result % M;
                }
                else if (symbol == '@')
                {
                    Console.WriteLine(result);
                }
            }


        }
    }
}