In this task, we ask you to write an answer to a question that involves “event duration", based on a given sentence. Here, event duration is defined as the understanding of how long events typically last. For example, “brushing teeth”, usually takes a few minutes. Note that a lot of the questions could have more than one correct answer. We only need a single most-likely answer. Please try to keep your "answer" as simple as possible. Concise and simple "answer" is preferred over those complex and verbose ones.

Ex Input:
Sentence: They are able to study the DNA of the organism that no longer lives on Earth. 
Question: How long did it take to study the DNA?

Ex Output:
three years.


Ex Input:
Sentence: The previous numismatic record holder was an 1804 U.S. silver dollar, which sold for $4.14 million in 1999. 
Question: How long did the bidding last for the 1804 U.S. silver dollar?

Ex Output:
seven minutes.


Ex Input:
Sentence: Natural Levees A flooding river often forms natural levees along its banks. 
Question: How long does it take for a river to form?

Ex Output:

a century.


