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: valbirse is a new municipality of the administrative district of jura bernois in the canton of berne in switzerland.
Example Output: valbirse

Example Input: the viol (rhymes with "mile") is a string instrument that is played with a bow.
Example Output: viol

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