Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

Ex Input:
Which model was married to photographer David Bailey for 10 years, from 1975?

Ex Output:
david bailey


Ex Input:
Which group of the 1970's featured Tony Iommi on guitar, Geezer Butler on bass and Bill Ward on drums?

Ex Output:
geezer butler


Ex Input:
Arlanda international airport is in which country?

Ex Output:

stockholm arlanda airport