tell me the difference between the amount of input and the amount of output until 10/06/2103 for patient 27451.
select ( select sum(inputevents_cv.amount) from inputevents_cv where inputevents_cv.icustay_id in ( select icustays.icustay_id from icustays where icustays.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 27451 ) ) and strftime('%y-%m-%d',inputevents_cv.charttime) <= '2103-10-06' ) - ( select sum(outputevents.value) from outputevents where outputevents.icustay_id in ( select icustays.icustay_id from icustays where icustays.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 27451 ) ) and strftime('%y-%m-%d',outputevents.charttime) <= '2103-10-06' )