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.

stenungsund is an urban area in the county of västra götaland in sweden.
stenungsund

vehari district is a district in the punjab province of pakistan.
vehari district

black mask is the name of two fictional batman villains who have a black skull and a black suit who in some cases is a crime boss leader.

black mask