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.

Input: Consider Input: the gandaki river is one of the major rivers of nepal.

Output: gandaki river


Input: Consider Input: the wisconsin river is a river in the united states.

Output: wisconsin river


Input: Consider Input: cottontail rabbits live in america.


Output: cottontail rabbit