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: 2ne1 is a pop group of female singers from south korea.
Example Output: 2ne1

Example Input: canada day is a national and an official holiday in canada celebrating its anniversary of confederation.
Example Output: canada day

Example Input: regent's university london is a private, not-for-profit university in london.
Example Output:
regent's university london