using System;

public class Program

{

    public static void Main()

    {

        var test = Program.MakeNegative(42);

        Console.WriteLine(test);

    }

    public static int MakeNegative(int number)

    {

        var myString = number.ToString();

        String myNewString = "";

        if(myString.Contains("-") || myString == "0")

        {

            myNewString = myString;

        }else

        {

            myNewString = "-" + myString;

        }

        var myNewNumber = int.Parse(myNewString);

        return myNewNumber;

    }

}