instruction: on 12/26/this year, what was first value of sao2 for patient 006-47576?
response: SELECT vitalperiodic.sao2 FROM vitalperiodic WHERE vitalperiodic.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '006-47576')) AND NOT vitalperiodic.sao2 IS NULL AND DATETIME(vitalperiodic.observationtime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-0 year') AND STRFTIME('%m-%d', vitalperiodic.observationtime) = '12-26' ORDER BY vitalperiodic.observationtime LIMIT 1