since 2105 what are the three most frequent drugs prescribed within the same month to the patients aged 30s after they have been diagnosed with prim cardiomyopathy nec.
select t3.drug from ( select t2.drug, dense_rank() over ( order by count(*) desc ) as c1 from ( select admissions.subject_id, diagnoses_icd.charttime from diagnoses_icd join admissions on diagnoses_icd.hadm_id = admissions.hadm_id where diagnoses_icd.icd9_code = ( select d_icd_diagnoses.icd9_code from d_icd_diagnoses where d_icd_diagnoses.short_title = 'prim cardiomyopathy nec' ) and strftime('%y',diagnoses_icd.charttime) >= '2105' ) as t1 join ( select admissions.subject_id, prescriptions.drug, prescriptions.startdate from prescriptions join admissions on prescriptions.hadm_id = admissions.hadm_id where admissions.age between 30 and 39 and strftime('%y',prescriptions.startdate) >= '2105' ) as t2 on t1.subject_id = t2.subject_id where t1.charttime < t2.startdate and datetime(t1.charttime,'start of month') = datetime(t2.startdate,'start of month') group by t2.drug ) as t3 where t3.c1 <= 3