instruction: get me the number of patients with blood lab test who have the diagnoses of dementia in conditions classifed elsewhere without behavioral disturbance.
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN diagnoses ON demographic.hadm_id = diagnoses.hadm_id INNER JOIN lab ON demographic.hadm_id = lab.hadm_id WHERE diagnoses.long_title = "Dementia in conditions classified elsewhere without behavioral disturbance" AND lab.fluid = "Blood"