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:
Who is the best selling novelist of all time?
answer:
Dame Agatha Mary Clarissa Christie, Lady Mallowan, DBE


question:
When did wicked open on broadway in nyc?
answer:

October 2003