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: tuff (from italian "tufo") is a type of rock produced by the eruption of volcanoes.
Example Output: tuff

Example Input: hiromasa yamamoto (山本浩正, yamamoto hiromasa, born 5 june 1979) is a japanese professional athlete.
Example Output: hiromasa yamamoto

Example Input: 98 degrees (stylized as 98°) is a grammy-nominated american pop and contemporary r&b band.
Example Output:
98 degrees