instruction: what is the number of patients whose discharge location is disch-tran to psych hosp and with procedure icd9 code 8674?
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN procedures ON demographic.hadm_id = procedures.hadm_id WHERE demographic.discharge_location = "DISCH-TRAN TO PSYCH HOSP" AND procedures.icd9_code = "8674"