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: "what are the two longest rivers in the united states?" whose answer is Mississippi River.
Each document should contain about 30 words, and these documents should contain useful information.

Query: two longest rivers in the united states
Useful Output:

Doc 1: The Mississippi River is one of the two longest rivers in the United States, measuring approximately 2,320 miles long.
Doc 2: Length. The Mississippi River is the second longest river in North America, flowing 2,350 miles from its source at Lake Itasca through the
Doc 3: 1. Missouri River · - 2,341 miles. Photo from Missouri River Institute[/caption] ; 2. Mississippi River · - 2,202 miles. Mississippi River Source
Doc 4: Ever wonder what rivers are the longest? Look at the graphic below to see our short list of long rivers.
Doc 5: 1. Missouri River. 2,540 ; 2. Mississippi River. 2,340 ; 3. Yukon River. 1,980 ; 4. Rio Grande. 1,900.