-er a-a a-c aaa aac aae aaf aak aao aap aar ac- aca acc ace acf ack aco acp acr aea aec aee aef aek aeo aep aer af- afa afc afe aff afk afo afp afr aka akc ake akk ako akp akr aoa aoc aoe aof aok aoo aop aor ap- apa apc ape apf apk apo app apr ar- ara arc are arf ark aro arp arr c-- caa cac cae caf cak cao cap car cca ccc cce ccf cck cco ccp ccr ce- cea cec cee cef cek ceo cep cer cfa cfc cfe cff cfk cfo cfp cfr cka ckc cko co- coa coc coe cof cok coo cop cor cpa cpc cpe cpf cpk cpo cpp cpr cra crc cre crf crk cro crp crr eaa eac eae eaf eak eao eap ear ec- eca ecc ece ecf eck eco ecr eea eec eee eef eek eeo eep eer ef- efa efc efe eff efo efp efr eka ekc eke ekf eko ekp ekr eo- eoa eoc eoe eof eok eoo eop eor ep- epa epc epe epf epo epp epr era erc ere erf erk ero erp err faa fac fae faf fak fao fap far fca fcc fce fcf fck fco fcp fcr fea fec fee fef fek feo fep fer ffa ffc ffe fff ffk ffo ffp ffr fka fkc fkf fkk fkp foa foc foe fof fok foo fop for fpa fpc fpe fpk fpo fpp fpr fra frc fre frf frk fro frp frr ka- kaa kac kae kaf kak kao kap kar kca kcc kce kck kcp kcr ke- kea kec kee kef kek keo kep ker kfa kfc kff kfo kkc kke kkk kkp kkr koa koc koe kof kok koo kop kor kpa kpc kpe kpf kpk kpo kpp kpr kra krc krf krk kro krp krr oaa oac oae oaf oak oao oap oar oc- oca occ ocf ock oco ocp ocr oea oec oee oef oeo oep oer of- ofa ofc ofe off ofo ofp ofr oka okc oke okk oko okp okr oo- ooa ooc oof ook ooo oop oor op- opa opc ope opf opk opo opp opr or- ora orc ore orf ork oro orp orr p-p paa pac pae paf pak pao pap par pca pcc pce pcf pck pco pcp pcr pea pec pee pef pek peo pep per pfa pfc pfe pff pfk pfo pfp pfr pka pkc pke pkf pko pkp pkr poa poc poe pof pok poo pop por ppa ppc ppe ppf ppk ppo ppp ppr pra prc pre prf prk pro prp prr ra- raa rac rae raf rak rao rap rar rca rcc rce rcf rco rcp rcr re- rea rec ree ref rek reo rep rer rfa rfc rfe rff rfk rfo rfp rfr rkc rke rkf rkk rko rkp roa roc roe rof rok roo rop ror rpa rpc rpe rpf rpk rpo rpp rpr rra rrc rrf rrk rrp rrr