instruction:
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.
question:
When did leningrad changed back to st petersburg?
answer:
6 September 1991


question:
When is season 3 of you me her coming out?
answer:
March 20, 2018


question:
Who are believed to be the direct ancestors to birds?
answer:

extinct non-avian dinosaurs