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.
--------
Question: san diego creek is a small northwest-flowing river in orange county, california.

Answer: san diego creek


Question: the saint petersburg stadium (russian: Стадион Санкт-Петербург; also called the krestovsky stadium or zenit arena) is an association football stadium in saint petersburg, russia.

Answer: saint petersburg stadium


Question: property law covers two types of property in the common law legal system, real property and personal property.

Answer:
property law