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:
jujutsu (柔術, jūjutsu) is an ancient japanese martial art.

Ex Output:
jujutsu


Ex Input:
kazuya maeda (born 8 september 1982) is a japanese football player.

Ex Output:
kazuya maeda


Ex Input:
grendel is one of the three antagonists in the poem "beowulf".

Ex Output:

grendel