How many cities does congressman Pierluisi Pedro represent?
SELECT COUNT(DISTINCT T1.city) FROM zip_data AS T1 INNER JOIN zip_congress AS T2 ON T1.zip_code = T2.zip_code INNER JOIN congress AS T3 ON T2.district = T3.cognress_rep_id WHERE T3.first_name = 'Pierluisi' AND T3.last_name = 'Pedro'