instruction: what is the number of patients born before 2035 who were diagnosed with preterm nec,1750-1999g?
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN diagnoses ON demographic.hadm_id = diagnoses.hadm_id WHERE demographic.dob_year < "2035" AND diagnoses.short_title = "Preterm NEC 1750-1999g"