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

namespace _3.CheckBrackets
{
    class CheckBrackets
    {
        static void Main()
        {
            Console.WriteLine("Enter a mathematical expression:");
            string str = Console.ReadLine();
            string newString = str;
            int leftBrackets = str.Length - str.Replace("(","").Length;
            int rightBrackets =str.Length - str.Replace(")","").Length;
            if (leftBrackets == rightBrackets)
            {
                for (int i = 0; i < leftBrackets; i++)
                {
                    int lastLeftBracketIndex = newString.LastIndexOf("(");
                    int matchingRigthBracketIndex = newString.IndexOf(")",lastLeftBracketIndex);
                    if (matchingRigthBracketIndex - lastLeftBracketIndex < 1)
                    {
                        Console.WriteLine("The expression {0} is incorrect:", str);
                        return;
                    }
                    else
                    {
                        newString = newString.Remove(lastLeftBracketIndex, matchingRigthBracketIndex - lastLeftBracketIndex + 1);
                    }
                }
                Console.WriteLine("The expression {0} is correct:", str);
            }
            else
            {
                Console.WriteLine("The expression {0} is incorrect:", str);
            }
        }
    }
}