instruction: get me the number of patients who are diagnosed with unspecified acute uri and are taking drug via po route.
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.short_title = "Acute uri NOS" AND prescriptions.route = "PO"