public class appel {

    private static int factorielle(int x)
    {
        if( x > 1)
        {
            return x*factorielle(x-1);
        }
        else
        {
            return 1;
        }
    }

    public static void main(String[] args) {

        int y = factorielle(Integer.parseInt(args[0]));
        System.out.println(y);
    }
}
