Given a text passage, come up with an appropriate title for it. The title should accurately represent what the main focus of the passage is. The title of a passage may be present in the first few sentences of the passage and/or be referred to multiple times in the passage. The title should be 1-5 words long.

Example input: The Beatles ' rooftop concert was the final public performance of the English rock band the Beatles . On 30 January 1969 , the band , with keyboardist Billy Preston , surprised a central London office and fashion district with an impromptu concert from the roof of the headquarters of the band 's multimedia corporation Apple Corps at 3 Savile Row . In a 42 - minute set , the Beatles were heard playing nine takes of five songs before the Metropolitan Police Service asked them to reduce the volume . Footage from the performance was later used in the 1970 documentary film Let It Be .

Example output: The Beatles' rooftop concert
Example explanation: 'The answer given is correct because it is an appropriate title as it is the main subject of the passage.
Q: The Louisiana Purchase ( French : Vente de la Louisiane '' Sale of Louisiana '' ) was the acquisition of the Louisiana territory ( 828,000 square miles or 2.14 million km2 ) by the United States from France in 1803 . The U.S. paid fifty million francs ( $11,250,000 / 9,100,000 ) and a cancellation of debts worth eighteen million francs ( $3,750,000 ) for a total of sixty - eight million francs ( $15 million , equivalent to $300 million in 2016 ) . The Louisiana territory included land from fifteen present U.S. states and two Canadian provinces . The territory contained land that forms Arkansas , Missouri , Iowa , Oklahoma , Kansas , and Nebraska ; the portion of Minnesota west of the Mississippi River ; a large portion of North Dakota ; a large portion of South Dakota ; the northeastern section of New Mexico ; the northern portion of Texas ; the area of Montana , Wyoming , and Colorado east of the Continental Divide ; Louisiana west of the Mississippi River ( plus New Orleans ) ; and small portions of land within the present Canadian provinces of Alberta and Saskatchewan . Its non-native population was around 60,000 inhabitants , of whom half were African slaves .
A:
Louisiana Purchase