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: the boeing international headquarters (colloquially known as the boeing building and formerly known as the morton international building) is a 36-floor skyscraper located in the near west side of chicago.
Example Output: boeing international headquarters

Example Input: the flag of thailand has five stripes in the colours red, white, and blue.
Example Output: flag of thailand

Example Input: bovinae is a subfamily of the even-toed ungulate family bovidae.
Example Output:
bovinae