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: milwaukee is the largest city in the state of wisconsin.
Example Output: milwaukee

Example Input: the sun belt conference is a group of college sports teams that play each other on the ncaa division i level.
Example Output: sun belt conference

Example Input: the sunflower ("helianthus annuus") is a living annual plant in the family asteraceae, with a large flower head ("capitulum").
Example Output:
sunflower