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 Q]: molar mass is the mass of a substance that has 6.022 10 atoms (avogadro's number).
[EX A]: molar mass

[EX Q]: cape hatteras is a cape on the coast of north carolina.
[EX A]: cape hatteras

[EX Q]: saint-simon, aisne is a commune.
[EX A]:
saint-simon, aisne