###HUMAN: provide the number of patients whose marital status is widowed and procedure long title is percutaneous (endoscopic) jejunostomy [pej]?, ###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 = "Percutaneous (endoscopic) jejunostomy [PEJ]"