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.
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Question: "hail to the chief" is the official presidential anthem of the united states.

Answer: hail to the chief


Question: yu gamdong (, ?

Answer: yu gamdong


Question: southwestern ontario is a subregion of southern ontario in the canadian province of ontario.

Answer:
southwestern ontario