what's the drug patient 56201 was prescribed two times in 02/2105?
select t1.drug from ( select prescriptions.drug, count( prescriptions.startdate ) as c1 from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 56201 ) and strftime('%y-%m',prescriptions.startdate) = '2105-02' group by prescriptions.drug ) as t1 where t1.c1 = 2