instruction:
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:
the saint petersburg stadium (russian: Стадион Санкт-Петербург; also called the krestovsky stadium or zenit arena) is an association football stadium in saint petersburg, russia.
answer:
saint petersburg stadium


question:
diana ross is a famous american soul and pop singer.
answer:
diana ross


question:
bernhard rensch (21 january 1900–4 april 1990) was a german evolutionary biologist, and ornithologist who did field work in indonesia and india.
answer:

bernhard rensch