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: police academy: the series, also known as police academy: the animated series, is an popular 1988 american animated television series based on the "police academy" series of films.
Example Output: police academy: the animated series

Example Input: murray albert olmstead (september 4, 1926 – november 16, 2015) was a canadian professional ice hockey left winger.
Example Output: bert olmstead

Example Input: seiji ozawa (born 1 september 1935) is a japanese conductor.
Example Output:
seiji ozawa