instruction: calculate patient 010-19726's stay length of the last stay in the icu.
response: SELECT STRFTIME('%j', patient.unitdischargetime) - STRFTIME('%j', patient.unitadmittime) FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '010-19726') AND NOT patient.unitadmittime IS NULL ORDER BY patient.unitadmittime DESC LIMIT 1