Joe is aiming to become the next supreme coder by trying to make his code smaller and smaller. His most recent project is a simple calculator which he reckons is super secure because of the "filters" he has in place. However, he thinks that he knows more than everyone around him. Put Joe in his place and grab the flag.
Ok, so we've got a webpage with calculator and a hint it's written in python.
I've found the flag using this payload