what was the total quantity of output from patient 9964 on the first icu visit?
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 = 9964 ) and icustays.outtime is not null order by icustays.intime asc limit 1 )