instruction: what is the number of patients whose admission location is phys referral/normal deli and procedure icd9 code is 9955?
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN procedures ON demographic.hadm_id = procedures.hadm_id WHERE demographic.admission_location = "PHYS REFERRAL/NORMAL DELI" AND procedures.icd9_code = "9955"