###HUMAN: count the number of patients whose marital status is widowed and procedure long title is laryngoscopy and other tracheoscopy., ###ASSISTANT: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN procedures ON demographic.hadm_id = procedures.hadm_id WHERE demographic.marital_status = "WIDOWED" AND procedures.long_title = "Laryngoscopy and other tracheoscopy"