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: nightmare disorder, also known as "dream anxiety disorder", is a sleep disorder characterized by frequent nightmares.
Example Output: nightmare disorder

Example Input: slow dazzle is the fifth studio album by multi-instrumentalist john cale.
Example Output: slow dazzle

Example Input: kraft foods is a business that makes packaged food.
Example Output:
kraft foods