how many hours have passed since the last time that patient 2957 stayed during the current hospital encounter in the ward 57?
select 24 * ( strftime('%j',current_time) - strftime('%j',transfers.intime) ) from transfers where transfers.icustay_id in ( select icustays.icustay_id from icustays where icustays.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 2957 and admissions.dischtime is null ) ) and transfers.wardid = 57 order by transfers.intime desc limit 1