what is the total amount of gammagard s/d that patient 32606 has been prescribed during their first hospital visit?
select sum(prescriptions.dose_val_rx) from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 32606 and admissions.dischtime is not null order by admissions.admittime asc limit 1 ) and prescriptions.drug = 'gammagard s/d'