what is the total amount of salsalate that has been prescribed to patient 69761 until 11/2105?
select sum(prescriptions.dose_val_rx) from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 69761 ) and prescriptions.drug = 'salsalate' and strftime('%y-%m',prescriptions.startdate) <= '2105-11'