TASK DEFINITION: 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.
PROBLEM: Who is the female guitarist in this is it?

SOLUTION: Orianthi Penny Panagaris

PROBLEM: What is on top of the space needle?

SOLUTION: observation deck

PROBLEM: How many tube stations are there in london?

SOLUTION:
270