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 occipital lobe is the back part of a mammal's brain.

Output: occipital lobe


Input: Consider Input: hawaii five-0 is a drama that first aired on september 20, 2010 on cbs, and is based on the original series.


Output: hawaii five-0