instruction: provide the number of patients whose age is less than 76 and diagnoses short title is migrne unsp wo ntrc mgrn?
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN diagnoses ON demographic.hadm_id = diagnoses.hadm_id WHERE demographic.age < "76" AND diagnoses.short_title = "Migrne unsp wo ntrc mgrn"