With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: San Francisco's Chinatown is the oldest stock exchange in North America.
text_B: Bob Carroll Jr. -LRB- August 12 , 1918 -- January 27 , 2007 -RRB- was a television writer notable for his creative role in the series I Love Lucy , the first four seasons of which he wrote with his professional partner Madelyn Pugh , and collaborator Jess Oppenheimer .. I Love Lucy. I Love Lucy. Madelyn Pugh. Madelyn Pugh. Jess Oppenheimer. Jess Oppenheimer. Bob Schiller and Bob Weiskopf later joined the series ' writing staff in the fifth season .. Bob Schiller. Bob Schiller. Bob Weiskopf. Bob Weiskopf
not_related.