-er a-a a-c aaa aac aad aae aak aao aap aar ac- aca acc acd ace ack aco acp acr ad- ada adc add ade adk ado adp adr aea aec aed aee aek aeo aep aer aka akc akd ake akk ako akp akr aoa aoc aod aoe aok aoo aop aor ap- apa apc apd ape apk apo app apr ar- ara arc ard are ark aro arp arr c-- caa cac cad cae cak cao cap car cca ccc ccd cce cck cco ccp ccr cda cdc cdd cde cdk cdo cdp cdr ce- cea cec ced cee cek ceo cep cer cka ckc ckd cko co- coa coc cod coe cok coo cop cor cpa cpc cpd cpe cpk cpo cpp cpr cra crc crd cre crk cro crp crr daa dac dad dae dak dao dap dar dca dcc dcd dce dck dco dcp dcr dda ddc ddd dde ddk ddo ddp ddr de- dea dec ded dee dek deo dep der dka dkc dke dkk dko dkp dkr doa doc dod doe dok doo dop dor dpa dpc dpd dpe dpk dpo dpp dpr dra drc drd dre drk dro drp drr eaa eac ead eae eak eao eap ear ec- eca ecc ecd ece eck eco ecr ed- eda edc edd ede edk edo edp edr eea eec eed eee eek eeo eep eer eka ekc ekd eke eko ekp ekr eo- eoa eoc eod eoe eok eoo eop eor ep- epa epc epd epe epo epp epr era erc erd ere erk ero erp err ka- kaa kac kad kae kak kao kap kar kca kcc kcd kce kck kcp kcr kda kdc kde kdk kdo kdp kdr ke- kea kec ked kee kek keo kep ker kkc kke kkk kkp kkr koa koc kod koe kok koo kop kor kpa kpc kpd kpe kpk kpo kpp kpr kra krc krd krk kro krp krr oaa oac oad oae oak oao oap oar oc- oca occ ocd ock oco ocp ocr oda odc odd ode odo odp odr oea oec oed oee oeo oep oer oka okc okd oke okk oko okp okr oo- ooa ooc ood ook ooo oop oor op- opa opc opd ope opk opo opp opr or- ora orc ord ore ork oro orp orr p-p paa pac pad pae pak pao pap par pca pcc pcd pce pck pco pcp pcr pda pdc pdd pde pdk pdo pdp pdr pea pec ped pee pek peo pep per pka pkc pkd pke pko pkp pkr poa poc pod poe pok poo pop por ppa ppc ppd ppe ppk ppo ppp ppr pra prc prd pre prk pro prp prr ra- raa rac rad rae rak rao rap rar rca rcc rcd rce rco rcp rcr rda rdc rdd rde rdo rdp rdr re- rea rec red ree rek reo rep rer rkc rke rkk rko rkp roa roc rod roe rok roo rop ror rpa rpc rpd rpe rpk rpo rpp rpr rra rrc rrd rrk rrp rrr