###HUMAN: provide the number of patients whose ethnicity is american indian/alaska native and drug code is benz1i?, ###ASSISTANT: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN prescriptions ON demographic.hadm_id = prescriptions.hadm_id WHERE demographic.ethnicity = "AMERICAN INDIAN/ALASKA NATIVE" AND prescriptions.formulary_drug_cd = "BENZ1I"