скобки

using System;
namespace Lectures
{
    class Program
    {
        static void Main()
        {
            string staples = "())(()";
            int numberOfOpenBrackets = 0;
            int numberOfCloseBrackets = 0;
            int numberOfAttachments = 0;
            int naturalNumber = 1;
            int counter = 0;
            bool correct = false;

            foreach (var symbol in staples)
            {
                switch (symbol)
                {
                    case '(':
                        numberOfOpenBrackets++;
                        counter++;
                        break;
                    case ')':
                        numberOfCloseBrackets++;
                        counter--;

                        if(counter < 0)
                        {
                            correct = true;
                        }
                        break;
                }
            }

            if (numberOfOpenBrackets == numberOfCloseBrackets && !correct)
            {
                numberOfAttachments = numberOfOpenBrackets - naturalNumber;
                Console.WriteLine($"Строка корректна, максимальная глубина равна {numberOfAttachments}.");
            }
            else
            {
                Console.WriteLine("Некорректная строка.");
            }
        }
    }
}