instruction: count the number of patients whose diagnoses long title is other pulmonary embolism and infarction and drug route is po.
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.long_title = "Other pulmonary embolism and infarction" AND prescriptions.route = "PO"