-er c-- ccc ccd cce cck ccr cdc cdd cde cdk cdr ce- cec ced cee cek cer ckc ckd crc crd cre crk crr dcc dcd dce dck dcr ddc ddd dde ddk ddr de- dec ded dee dek der dkc dke dkk dkr drc drd dre drk drr ec- ecc ecd ece eck ecr ed- edc edd ede edk edr eec eed eee eek eer ekc ekd eke ekr erc erd ere erk err kcc kcd kce kck kcr kdc kde kdk kdr ke- kec ked kee kek ker kkc kke kkk kkr krc krd krk krr rcc rcd rce rcr rdc rdd rde rdr re- rec red ree rek rer rkc rke rkk rrc rrd rrk rrr