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: paranthropus is an extinct genus of robust australopithecines.
Example Output: paranthropus

Example Input: the artemision zeus is a greek bronze statue.
Example Output: artemision zeus

Example Input: the tanggu truce resulted in the "de facto" recognition of manchukuo by the kuomingtang government, and acceptance of the loss of rehe.
Example Output:
tanggu truce