using System;

public class Program

{

    public static void Main()

    {

        int product = 1;

        int num = 1;

        while (num < 11)

        {

            product = product*num;

            num++;

        }

        Console.WriteLine("The product of the first 10 numbers is: " + product + ".");

        int num2 = 1;

        while (num2 < 21)

        {

            Console.WriteLine(num2);

            product = product*num2;

            num2++;

        }

        Console.WriteLine("The product of the first 20 numbers is: " + product + ".");

    }

}