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.
--------
Question: michigan avenue is a major north-south street in chicago.

Answer: michigan avenue


Question: the calculus of variations is a field of mathematical analysis.

Answer: calculus of variations


Question: yoshikazu goto (後藤 義一, goto yoshikazu, born february 20, 1964) is a japanese professional athlete.

Answer:
yoshikazu goto