using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Enter a number: ");

        int num = int.Parse(Console.ReadLine());

        Console.WriteLine("The factorial of " + num + " is " + calculateFactorial(num));

    }

    private static int calculateFactorial(int number)

    {

        int factorial = 1;

        while (number > 1)

        {

            factorial *= number--;

        }

        return factorial;

    }

}