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.

[EX Q]: cumulative voting is a system for doing an election.
[EX A]: cumulative voting

[EX Q]: jujutsu (柔術, jūjutsu) is an ancient japanese martial art.
[EX A]: jujutsu

[EX Q]: regent's canal is a canal in england.
[EX A]:
regent's canal