question: How many books are in Isaac Asimov's Foundation series?
answerText: 7
questionEntity.name: Q1564644
questionEntity.entityType: entity
questionEntity.label: Foundation series
questionEntity.mention: Foundation
questionEntity.name: Q34981
questionEntity.entityType: entity
questionEntity.label: Isaac Asimov
questionEntity.mention: Isaac Asimov's
answerEntity.name: Q753894
answerEntity.label: Foundation
answerEntity.name: Q839800
answerEntity.label: Foundation and Empire
answerEntity.name: Q853927
answerEntity.label: Second Foundation
answerEntity.name: Q932592
answerEntity.label: Foundation’s Edge
answerEntity.name: Q1050014
answerEntity.label: Foundation and Earth
answerEntity.name: Q783533
answerEntity.label: Prelude to Foundation
answerEntity.name: Q938629
answerEntity.label: Forward the Foundation