instruction: tell me the maximum heartrate for patient 016-18150's body on last month/05?
response: SELECT MAX(vitalperiodic.heartrate) FROM vitalperiodic WHERE vitalperiodic.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '016-18150')) AND NOT vitalperiodic.heartrate IS NULL AND DATETIME(vitalperiodic.observationtime, 'start of month') = DATETIME(CURRENT_TIME(), 'start of month', '-1 month') AND STRFTIME('%d', vitalperiodic.observationtime) = '05'