In this task, you're given an open-domain question. Your task is to provide an answer to the given question. There is only one unique answer for each question. Your answer should be short, and refer to an entity, date, number, etc. Do not put your answer in the context of a sentence.

[Q]: When was season 2 of this is us filmed?
[A]: 2017


[Q]: Who plays alex von strucker in agents of shield?
[A]: Spencer Treat Clark


[Q]: How many types of ion channels are there?
[A]:
over 300