Solve Expressions

using System;
using System.Linq;

namespace Solve_expression
{
    class Program
    {
        public static char[] operators = new char[] { '+', '-', '*', '/' };
        static void Main(string[] args)
        {
            string input = Console.ReadLine();

            Console.WriteLine(CalculateExpression(input));
        }

        static int CalculateExpression(string input)
        {
            char expressionOperator = input.Where(x => operators.Contains(x)).FirstOrDefault();
            string[] numbers = input.Split(expressionOperator, 2);

            if (!(input.Contains('(') && input.Contains(')')))
            {
                if (numbers.Length == 1)
                {
                    return int.Parse(numbers[0]);
                }

                return Evaluate(int.Parse(numbers[0]), int.Parse(numbers[1]), expressionOperator);
            }

            return Evaluate(int.Parse(numbers[0]), CalculateExpression(numbers[1].Substring(1, numbers[1].Length - 2)), expressionOperator);
        }
        static int Evaluate (int a, int b, char Operator)
        {
            switch (Operator)
            {
                case '+':
                    return a + b;
                case '-':
                    return a - b;
                case '*':
                    return a * b;
                case '/':
                    return a / b;
                default: return 0;
            }
        }
    }
}