-er a-a a-c aaa aac aad aae aak aar ac- aca acc acd ace ack acr ad- ada adc add ade adk adr aea aec aed aee aek aer aka akc akd ake akk akr ar- ara arc ard are ark arr c-- caa cac cad cae cak car cca ccc ccd cce cck ccr cda cdc cdd cde cdk cdr ce- cea cec ced cee cek cer cka ckc ckd cra crc crd cre crk crr daa dac dad dae dak dar dca dcc dcd dce dck dcr dda ddc ddd dde ddk ddr de- dea dec ded dee dek der dka dkc dke dkk dkr dra drc drd dre drk drr eaa eac ead eae eak ear ec- eca ecc ecd ece eck ecr ed- eda edc edd ede edk edr eea eec eed eee eek eer eka ekc ekd eke ekr era erc erd ere erk err ka- kaa kac kad kae kak kar kca kcc kcd kce kck kcr kda kdc kde kdk kdr ke- kea kec ked kee kek ker kkc kke kkk kkr kra krc krd krk krr ra- raa rac rad rae rak rar rca rcc rcd rce rcr rda rdc rdd rde rdr re- rea rec red ree rek rer rkc rke rkk rra rrc rrd rrk rrr