using System;

using System.Text.RegularExpressions;

public class Program

{

    public static int Multiplication (int x, int y) {

        return x*y;

    }

    public static int Division (int x, int y) {

        return x/y;

    }

    public static void Main()

    {

        Console.WriteLine("Insert Equation:");

        var expression = Console.ReadLine();

        //How to do this more efficiently

        int [] index = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

        int [] firstNumberInt = {0,0,0,0,0,0,0,0,0,0,0};

        string [] firstNumberString = {"","","","","","","","","","","","",""};

        for(int i = 0; i < expression.Length; i++) {

            firstNumberString[i] = Regex.Match(expression, @"\d+").Value;

            firstNumberInt[i] = Convert.ToInt32(firstNumberString[i]);

            index[i] = expression.IndexOf(firstNumberString[i]);

            expression = expression.Remove(index[i],firstNumberString[i].Length);

        }

        if(expression.Contains("*")) {

            var multiplicationExpression = expression.IndexOf("*");

            Console.WriteLine(Multiplication(firstNumberInt[multiplicationExpression],firstNumberInt[multiplicationExpression+1]));

            expression = expression.Replace("*","");

            //How to get removeAt to work?

            //Array.removeAt(firstNumberInt, multiplicationExpression);

            //Take multiplicationExpression and multiplicationExpression - 1 out of firstNumberInt... How to do?

        } 

        if(expression.Contains("/")){ 

            var divisionExpression = expression.IndexOf("/");

            Console.WriteLine(Division(firstNumberInt[divisionExpression],firstNumberInt[divisionExpression+1]));

            expression = expression.Replace("/"," ");

        } 

        if(expression.Contains("+")) {

            Console.WriteLine("Has addition or subtraction");   

        } 

        if (expression.Contains("-")) {

        }

        if (expression.Contains("^")||expression.Contains("(")||expression.Contains(")")) {

            Console.WriteLine("Sorry, but we can't solve this problem");

        }

    }

}