internal class Program
{


    public static int ValidationNumber() // function for validating a number and ensuring data has been entered
    {
        int UserInput; // defines the UserInput integer
        do // defines the start of the do while loop
        {
            try // tries the code and let's it run
            {

                UserInput = int.Parse(Console.ReadLine()); // takes the users input and converts it into an integer using parse
                if (UserInput < 1) // checks if user input is less than  1
                {
                    Console.WriteLine("Error, please enter a number greater than or equal to 1."); // outputs minimum user input to user
                }
                else
                {
                    break; // breaks out of loop
                }
            }
            catch (FormatException) // performs the code in the event that a format exception has occurred, aka data that shouldn't be entered
            {
                Console.WriteLine("Error, unsuitable data entered. Please enter valid data"); // informs the user they have entered unsuitable data
            }

        } while (true); // will continuously perform the do while loop until a break has been reached

        return UserInput;
    }


    private static void Main(string[] args)
    {
        int Radius = 0; // defines radius
        int Height = 0; // defines height
        double Pi = 3.142; // defines pi
        double Volume = 0; // defines volume

        Console.WriteLine("Please enter the first number");
        Radius = ValidationNumber(); // performs validationnumber method on Radius
        Console.WriteLine("Please enter the second number");
        Height = ValidationNumber(); // performs validationnumber method on height

        int RadiusSquared = Radius * Radius; // calculates radius squared by performing radius * radius
        Volume = Pi * RadiusSquared * Height / 3; // sets volume to pi * radiussquared * height / 3

        Volume = Math.Round(Volume,2); // rounds volume to 2 decimal places

        Console.WriteLine("The volume is " + Volume); // prints volume to user
        Console.ReadKey(); // waits for input to close program
         

    }
}