-er c-- ccc ccd cce cck cco ccp ccr cdc cdd cde cdk cdo cdp cdr ce- cec ced cee cek ceo cep cer ckc ckd cko co- coc cod coe cok coo cop cor cpc cpd cpe cpk cpo cpp cpr crc crd cre crk cro crp crr dcc dcd dce dck dco dcp dcr ddc ddd dde ddk ddo ddp ddr de- dec ded dee dek deo dep der dkc dke dkk dko dkp dkr doc dod doe dok doo dop dor dpc dpd dpe dpk dpo dpp dpr drc drd dre drk dro drp drr ec- ecc ecd ece eck eco ecr ed- edc edd ede edk edo edp edr eec eed eee eek eeo eep eer ekc ekd eke eko ekp ekr eo- eoc eod eoe eok eoo eop eor ep- epc epd epe epo epp epr erc erd ere erk ero erp err kcc kcd kce kck kcp kcr kdc kde kdk kdo kdp kdr ke- kec ked kee kek keo kep ker kkc kke kkk kkp kkr koc kod koe kok koo kop kor kpc kpd kpe kpk kpo kpp kpr krc krd krk kro krp krr oc- occ ocd ock oco ocp ocr odc odd ode odo odp odr oec oed oee oeo oep oer okc okd oke okk oko okp okr oo- ooc ood ook ooo oop oor op- opc opd ope opk opo opp opr or- orc ord ore ork oro orp orr p-p pcc pcd pce pck pco pcp pcr pdc pdd pde pdk pdo pdp pdr pec ped pee pek peo pep per pkc pkd pke pko pkp pkr poc pod poe pok poo pop por ppc ppd ppe ppk ppo ppp ppr prc prd pre prk pro prp prr rcc rcd rce rco rcp rcr rdc rdd rde rdo rdp rdr re- rec red ree rek reo rep rer rkc rke rkk rko rkp roc rod roe rok roo rop ror rpc rpd rpe rpk rpo rpp rpr rrc rrd rrk rrp rrr