With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: PlayStation 4 does not emphasize integration with other devices and services.
text_B: Petr Horava is a Czech string theorist .. Czech. Czechs. string theorist. superstring theory. He is a professor of physics at the University of California , Berkeley , where he teaches courses on quantum field theory and string theory .. quantum field theory. quantum field theory. string theory. string theory. Horava is a member of the theory group at Lawrence Berkeley National Laboratory .. Lawrence Berkeley National Laboratory. LBNL
not_related.