instruction: what the first height of patient 28447 this month.
response: SELECT chartevents.valuenum FROM chartevents WHERE chartevents.icustay_id IN (SELECT icustays.icustay_id FROM icustays WHERE icustays.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 28447)) AND chartevents.itemid IN (SELECT d_items.itemid FROM d_items WHERE d_items.label = 'admit ht' AND d_items.linksto = 'chartevents') AND DATETIME(chartevents.charttime, 'start of month') = DATETIME(CURRENT_TIME(), 'start of month', '-0 month') ORDER BY chartevents.charttime LIMIT 1