Enigmanation

using System;
using System.Collections.Generic;
class Enigmanation
{
    static double CalcBrackets(string expr)
    {
        char[] expression = expr.ToCharArray();
        double result = expression[0] - '0';

        for (int i = 2; i < expression.Length; i += 2)
        {
            if (expression[i - 1] == '+') result += (expression[i] - '0');
            else if (expression[i - 1] == '-') result -= (expression[i] - '0');
            else if (expression[i - 1] == '%') result %= (expression[i] - '0');
            else if (expression[i - 1] == '*') result *= (expression[i] - '0');
        }
        return result;
    }
    static void Main()
    {
        string entry = Console.ReadLine();
        char[] input = entry.ToCharArray();
        List<string> list = new List<string>();

        double result = 0;
        for (int i = 0; i < input.Length; i++)
        {
            if (input[i] == '(')
            {
                int endInBracketIndex = entry.IndexOf(')', i);
                string insideBrackets = entry.Substring(i + 1, endInBracketIndex - i - 1);
                list.Add(CalcBrackets(insideBrackets).ToString());
                i = endInBracketIndex;
            }
            if (input[i] == ')') i += 1;
            list.Add(input[i].ToString());
        }

        result = double.Parse(list[0]);
        for (int i = 2; i < list.Count; i++)
        {
            if (list[i - 1] == "+") result += double.Parse(list[i]);
            else if (list[i - 1] == "-") result -= double.Parse(list[i]);
            else if (list[i - 1] == "%") result %= double.Parse(list[i]);
            else if (list[i - 1] == "*") result *= double.Parse(list[i]);
        }
        Console.WriteLine("{0:f3}", result);
    }
}