Enigmanation

using System;
using System.Text;

class Enigmanation
{
    static void Main()
    {
        string input = Console.ReadLine();
        StringBuilder ready = new StringBuilder();

        int counter = 0;
        while (true)
        {
            char ch = input[counter];
            if (char.IsDigit(ch)) ready.Append(ch + " ");
            else if (ch == '+' || ch == '-' || ch == '*' || ch == '%') ready.Append(ch + " ");
            else // if (ch == '(')
            {
                counter++;
                char next = input[counter];
                int result = int.Parse(next.ToString());
                while (true)
                {
                    counter++;
                    next = input[counter];
                    if (next == '+' || next == '-' || next == '*' || next == '%')
                    {
                        counter++;
                        int num = int.Parse(input[counter].ToString());
                        switch (next)
                        {
                            case '+': result += num; break;
                            case '-': result -= num; break;
                            case '*': result *= num; break;
                            case '%': result %= num; break;
                        }
                    }
                    if (next == ')') break;
                }
                ready.Append(result + " ");
            }
            counter++;
            if (input[counter] == '=')
            {
                ready.Append("=");
                break;
            }
        }

        int count = 0;
        for (int i = 0; i < ready.Length; i++)
        {
            if (ready[i] == ' ') count++;
        }
        string s = ready.ToString();
        string[] str = s.Split(' ');

        long output = long.Parse(str[0]);

        for (int i = 1; str[i] != "="; i += 2)
        {
            char op = char.Parse(str[i]);
            long num = long.Parse(str[i + 1]);
            switch (op)
            {
                case '+': output += num; break;
                case '-': output -= num; break;
                case '*': output *= num; break;
                case '%': output %= num; break;
            }
        }

        Console.WriteLine("{0:F3}", output);
    }
}