what is the monthly minimum amount of stool out stool that patient 61339 had until 71 months ago?
select min(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 = 61339 ) ) and outputevents.itemid in ( select d_items.itemid from d_items where d_items.label = 'stool out stool' and d_items.linksto = 'outputevents' ) and datetime(outputevents.charttime) <= datetime(current_time,'-71 month') group by strftime('%y-%m',outputevents.charttime)