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.

Ex Input:
an aloha shirt (also known as a hawaiian shirt) is a type of shirt that comes from hawaii.

Ex Output:
aloha shirt


Ex Input:
henry's marriage to catherine of aragon was finally annulled in the following may by archbishop cranmer, thus ending the first of henry's 6 marriages.

Ex Output:
catherine of aragon


Ex Input:
the ming dynasty was the family of emperors who led china from 1368 to 1644.

Ex Output:

ming dynasty