using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Votre nombre ?");

        int n = Convert .ToInt32 (Console.ReadLine() ) ;

        int m = 1;

        if (n >= 1)

        {

            while (n > 0)

            {

                m = m * n;

                n = n - 1;

            }

        Console.WriteLine("Factorielle:" + m);

        } else {

            Console.WriteLine("Impossible");

        }

    }

}