Generate a topic word for the given sentence. A topic word is usually the name of a person, place, animal, concept or object the sentence is focusing on.

Example Input: the jungle book is a collection of stories written by rudyard kipling.
Example Output: the jungle book

Example Input: the bucket list is a 2007 american comedy-drama movie.
Example Output: the bucket list

Example Input: the pentagon shopping centre (known locally as 'the pentagon') is a shopping centre in chatham, kent.
Example Output:
pentagon shopping centre