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.

bici bici or bicibici muhallebisi is a turkish dessert.
bici bici

an electronic book (also called an e-book, ebook or digital book) is a book in digital form.
e-book

hepatitis b is a disease of the liver.

hepatitis b

