instruction: count the number of patients whose diagnoses icd9 code is e9300 and drug type is main?
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN diagnoses ON demographic.hadm_id = diagnoses.hadm_id INNER JOIN prescriptions ON demographic.hadm_id = prescriptions.hadm_id WHERE diagnoses.icd9_code = "E9300" AND prescriptions.drug_type = "MAIN"