How many distinct locations have the things with service detail 'Unsatisfied' been located in?
SELECT count ( DISTINCT T2.Location_Code )  FROM Things AS T1 JOIN Timed_Locations_of_Things AS T2 ON T1.thing_id   =   T2.thing_id WHERE T1.service_details   =   'Unsatisfied'
distinct locations = COUNT(DISTINCT Location_Code); things with service detail 'Unsatisfied' refers to WHERE service_details = 'Unsatisfied';