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:
nexon corporation is a korean gaming corporation and developer of online games and mmorpgs.

Ex Output:
nexon

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:
bios, computing, stands for basic input/output system.

Ex Output:
bios