Detailed Instructions: This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
Q: Passage: The house which forms the architectural core of the palace was built for the first Duke of Buckingham and Normanby in 1703 to the design of William Winde. The style chosen was of a large, three-floored central block with two smaller flanking service wings. Buckingham House was eventually sold by Buckingham's descendant, Sir Charles Sheffield, in 1761 to George III for 21,000. Sheffield's leasehold on the mulberry garden site, the freehold of which was still owned by the royal family, was due to expire in 1774. Question: How many flanking service wings did the original Buckingham House have?
A:
two