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:
child development refers to biological, psychological and emotional changes that happen in humans between birth and the end of adolescence, at which time the individual goes from dependence to independence.

Ex Output:
child development


Ex Input:
the capital of hunedoara county is deva.

Ex Output:
hunedoara county


Ex Input:
heather menzies-urich (december 3, 1949 – december 24, 2017) was a canadian-american model, activist and actress.

Ex Output:

heather menzies