instruction: provide the number of patients who have ed route of drug administration and are diagnosed with coronary atherosclerosis of unspecified type of vessel, native or graft.
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 = "Cor ath unsp vsl ntv/gft" AND prescriptions.route = "ED"