what difference in weight did patient 8016 have second measured on the last hospital visit compared to the value first measured on the last hospital visit?
select ( select chartevents.valuenum from chartevents where chartevents.icustay_id in ( select icustays.icustay_id from icustays where icustays.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 8016 and admissions.dischtime is not null order by admissions.admittime desc limit 1 ) ) and chartevents.itemid in ( select d_items.itemid from d_items where d_items.label = 'admit wt' and d_items.linksto = 'chartevents' ) order by chartevents.charttime asc limit 1 offset 1 ) - ( select chartevents.valuenum from chartevents where chartevents.icustay_id in ( select icustays.icustay_id from icustays where icustays.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 8016 and admissions.dischtime is not null order by admissions.admittime desc limit 1 ) ) and chartevents.itemid in ( select d_items.itemid from d_items where d_items.label = 'admit wt' and d_items.linksto = 'chartevents' ) order by chartevents.charttime asc limit 1 )