what were the total amount of d20w intake that patient 30171 had received on 05/30/2101?
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 = 30171 ) ) and inputevents_cv.itemid in ( select d_items.itemid from d_items where d_items.label = 'd20w' and d_items.linksto = 'inputevents_cv' ) and strftime('%y-%m-%d',inputevents_cv.charttime) = '2101-05-30'