-er a-a a-c aaa aac aad aae aak aao aar ac- aca acc acd ace ack aco acr ad- ada adc add ade adk ado adr aea aec aed aee aek aeo aer aka akc akd ake akk ako akr aoa aoc aod aoe aok aoo aor ar- ara arc ard are ark aro arr c-- caa cac cad cae cak cao car cca ccc ccd cce cck cco ccr cda cdc cdd cde cdk cdo cdr ce- cea cec ced cee cek ceo cer cka ckc ckd cko co- coa coc cod coe cok coo cor cra crc crd cre crk cro crr daa dac dad dae dak dao dar dca dcc dcd dce dck dco dcr dda ddc ddd dde ddk ddo ddr de- dea dec ded dee dek deo der dka dkc dke dkk dko dkr doa doc dod doe dok doo dor dra drc drd dre drk dro drr eaa eac ead eae eak eao ear ec- eca ecc ecd ece eck eco ecr ed- eda edc edd ede edk edo edr eea eec eed eee eek eeo eer eka ekc ekd eke eko ekr eo- eoa eoc eod eoe eok eoo eor era erc erd ere erk ero err ka- kaa kac kad kae kak kao kar kca kcc kcd kce kck kcr kda kdc kde kdk kdo kdr ke- kea kec ked kee kek keo ker kkc kke kkk kkr koa koc kod koe kok koo kor kra krc krd krk kro krr oaa oac oad oae oak oao oar oc- oca occ ocd ock oco ocr oda odc odd ode odo odr oea oec oed oee oeo oer oka okc okd oke okk oko okr oo- ooa ooc ood ook ooo oor or- ora orc ord ore ork oro orr ra- raa rac rad rae rak rao rar rca rcc rcd rce rco rcr rda rdc rdd rde rdo rdr re- rea rec red ree rek reo rer rkc rke rkk rko roa roc rod roe rok roo ror rra rrc rrd rrk rrr