instruction: what is the number of patients who had a implantation of heart pacemaker - temporary procedure since 6 years ago?
response: SELECT COUNT(DISTINCT patient.uniquepid) FROM patient WHERE patient.patientunitstayid IN (SELECT treatment.patientunitstayid FROM treatment WHERE treatment.treatmentname = 'implantation of heart pacemaker - temporary' AND DATETIME(treatment.treatmenttime) >= DATETIME(CURRENT_TIME(), '-6 year'))