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: bothnian bay (; ) is a bay in the northest of the gulf of bothnia.
Example Output: bothnian bay

Example Input: henan is a province of the people's republic of china.
Example Output: henan

Example Input: lassie lou ahern (june 25, 1920 – february 15, 2018) was an american former child actress and television actress.
Example Output:
lassie lou ahern