check is failling

I would like to give some feedback about ...

From: https://checkio.org/mission/digit-stack/solve/

HTTP_USER_AGENT:

Mozilla/5.0 (X11; Linux i686; rv:38.0) Gecko/20100101 Firefox/38.0

The code is working when i use the console with 'Try it' but it's failling and say my result is 0 when i 'Run and Check'