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.

Example Input: institut d'optique graduate school (supoptique) is a renowned graduate engineering school in france.
Example Output: institut d'optique graduate school

Example Input: metis is the goddess of wisdom in greek mythology.
Example Output: metis

Example Input: nick clegg was a member of the european parliament (mep) from 1999 to 2004 and was first elected as a liberal democrat mp in the 2005 general election.
Example Output:
nick clegg