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]: the wii u is a video game console that was released by nintendo on november 18, 2012, and is the successor of the wii.
[EX A]: wii u

[EX Q]: songkran is a festival held every year in thailand on april 13.
[EX A]: songkran

[EX Q]: a sawfly is an insect belonging to suborder symphyta of the order hymenoptera.
[EX A]:
sawfly