You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "who is the longest serving prime minister of uk?" whose answer is Sir Robert Walpole.
Each document should contain about 30 words, and these documents should contain useful information.

Query: longest serving prime minister uk
Useful Output:

Doc 1: The longest-serving prime minister was Robert Walpole, who was in the role for 20 years and 315 days, from April 3, 1721, to Feb. 11, 1742.
Doc 2: From Winston Churchill to Liz Truss, Queen Elizabeth ll worked with 15 British prime ministers in her 70-year reign. Here are some key
Doc 3: Lord John Prescott has died at the age of 86. He was Britain's longest-serving deputy prime minister - at Sir Tony Blair's side for a decade after Labour's
Doc 4:  Britain's longest-serving prime minister Margaret Thatcher. But instead of lasting more than 4,100 days in office - a feat achieved by
Doc 5: - William Pitt the Younger: (1783-1801; 1804-06) 18 years 343 days. - Robert Banks Jenkinson, Earl of Liverpool: (1812-27) 14 years 305 days. - Robert Gascoyne-