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 Input:
lactarius torminosus, commonly known as the woolly milkcap or the bearded milkcap, is a mushroom in the genus "lactarius".

Ex Output:
lactarius torminosus

Ex Input:
central plaza is a skyscraper in hong kong.

Ex Output:
central plaza

Ex Input:
george clifton james (may 29, 1920 april 15, 2017) was a retired american actor.

Ex Output:
clifton james