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: the somatic nervous system (sns) is part of the peripheral nervous system.
Example Output: somatic nervous system

Example Input: a hamburger is a type of sandwich with cooked ground meat between the two halves of a bun.
Example Output: hamburger

Example Input: the african golden cat ("profelis aurata") is a medium-sized cat.
Example Output:
african golden cat