-er a-a a-c aaa aac aad aae aaf aak aao aar ac- aca acc acd ace acf ack aco acr ad- ada adc add ade adf adk ado adr aea aec aed aee aef aek aeo aer af- afa afc afd afe aff afk afo afr aka akc akd ake akk ako akr aoa aoc aod aoe aof aok aoo aor ar- ara arc ard are arf ark aro arr c-- caa cac cad cae caf cak cao car cca ccc ccd cce ccf cck cco ccr cda cdc cdd cde cdf cdk cdo cdr ce- cea cec ced cee cef cek ceo cer cfa cfc cfd cfe cff cfk cfo cfr cka ckc ckd cko co- coa coc cod coe cof cok coo cor cra crc crd cre crf crk cro crr daa dac dad dae daf dak dao dar dca dcc dcd dce dcf dck dco dcr dda ddc ddd dde ddf ddk ddo ddr de- dea dec ded dee def dek deo der dfa dfc dfd dfe dff dfk dfo dfr dka dkc dke dkk dko dkr doa doc dod doe dof dok doo dor dra drc drd dre drk dro drr eaa eac ead eae eaf eak eao ear ec- eca ecc ecd ece ecf eck eco ecr ed- eda edc edd ede edf edk edo edr eea eec eed eee eef eek eeo eer ef- efa efc efd efe eff efo efr eka ekc ekd eke ekf eko ekr eo- eoa eoc eod eoe eof eok eoo eor era erc erd ere erf erk ero err faa fac fad fae faf fak fao far fca fcc fcd fce fcf fck fco fcr fda fdc fdd fde fdf fdk fdo fdr fea fec fed fee fef fek feo fer ffa ffc ffd ffe fff ffk ffo ffr fka fkc fkf fkk foa foc foe fof fok foo for fra frc frd fre frf frk fro frr ka- kaa kac kad kae kaf kak kao kar kca kcc kcd kce kck kcr kda kdc kde kdf kdk kdo kdr ke- kea kec ked kee kef kek keo ker kfa kfc kfd kff kfo kkc kke kkk kkr koa koc kod koe kof kok koo kor kra krc krd krf krk kro krr oaa oac oad oae oaf oak oao oar oc- oca occ ocd ocf ock oco ocr oda odc odd ode odf odo odr oea oec oed oee oef oeo oer of- ofa ofc ofd ofe off ofo ofr oka okc okd oke okk oko okr oo- ooa ooc ood oof ook ooo oor or- ora orc ord ore orf ork oro orr ra- raa rac rad rae raf rak rao rar rca rcc rcd rce rcf rco rcr rda rdc rdd rde rdf rdo rdr re- rea rec red ree ref rek reo rer rfa rfc rfd rfe rff rfk rfo rfr rkc rke rkf rkk rko roa roc rod roe rof rok roo ror rra rrc rrd rrf rrk rrr