tell me the difference between the input and output of patient 19427 on last month/19?
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 = 19427 ) ) and datetime(inputevents_cv.charttime,'start of month') = datetime(current_time,'start of month','-1 month') and strftime('%d',inputevents_cv.charttime) = '19' ) - ( 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 = 19427 ) ) and datetime(outputevents.charttime,'start of month') = datetime(current_time,'start of month','-1 month') and strftime('%d',outputevents.charttime) = '19' )