how many times has patient 20441 received a po intake since 1987 days ago?
select count(*) 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 = 20441 ) ) and inputevents_cv.itemid in ( select d_items.itemid from d_items where d_items.label = 'po intake' and d_items.linksto = 'inputevents_cv' ) and datetime(inputevents_cv.charttime) >= datetime(current_time,'-1987 day')