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 president in america?" whose answer is Franklin D. Roosevelt.
Each document should contain about 30 words, and these documents should contain useful information.

Query: longest serving president in america
Useful Output:

Doc 1: Longest-Serving Party Leaders ; McConnellMitch McConnell (R-KY), 18, 1985-present ; MansfieldMichael J. Mansfield (D-MT), 16, 1953-1977 ; RobinsonJoseph T.
Doc 2: The longest-serving president was Franklin D. Roosevelt, who died shortly into his fourth term in office. (The 22nd Amendment, ratified in 1951, limited to
Doc 3: The longest term ever served was by Franklin D. Roosevelt, who is the only president to have been elected more than two times; although he
Doc 4: Franklin D. Roosevelt is the longest-serving U.S. President. He served four terms from 1933 to 1945, leading the country through the Great Depression and World
Doc 5: Who Was The Longest Serving President? Franklin D. Roosevelt, the 32nd president of the United States, served an astonishing four terms in