-er a-a a-c aaa aac aae aaf aak aao aap aar aas ac- aca acc ace acf ack aco acp acr acs aea aec aee aef aek aeo aep aer aes af- afa afc afe aff afk afo afp afr afs aka akc ake akk ako akp akr aks aoa aoc aoe aof aok aoo aop aor aos ap- apa apc ape apf apk apo app apr aps ar- ara arc are arf ark aro arp arr ars as- asa asc ase asf ask aso asp asr ass c-- caa cac cae caf cak cao cap car cas cca ccc cce ccf cck cco ccp ccr ccs ce- cea cec cee cef cek ceo cep cer ces cfa cfc cfe cff cfk cfo cfp cfr cfs cka ckc cko cks co- coa coc coe cof cok coo cop cor cos cpa cpc cpe cpf cpk cpo cpp cpr cps cra crc cre crf crk cro crp crr crs csa csc cse csf csk cso csp csr css eaa eac eae eaf eak eao eap ear eas ec- eca ecc ece ecf eck eco ecr ecs eea eec eee eef eek eeo eep eer ees ef- efa efc efe eff efo efp efr efs eka ekc eke ekf eko ekp ekr eks eo- eoa eoc eoe eof eok eoo eop eor eos ep- epa epc epe epf epo epp epr eps era erc ere erf erk ero erp err ers es- esa esc ese esf esk eso esp esr ess faa fac fae faf fak fao fap far fas fca fcc fce fcf fck fco fcp fcr fcs fea fec fee fef fek feo fep fer fes ffa ffc ffe fff ffk ffo ffp ffr ffs fka fkc fkf fkk fkp foa foc foe fof fok foo fop for fos fpa fpc fpe fpk fpo fpp fpr fps fra frc fre frf frk fro frp frr frs fsa fsc fse fsf fsk fso fsp fsr fss ka- kaa kac kae kaf kak kao kap kar kas kca kcc kce kck kcp kcr kcs ke- kea kec kee kef kek keo kep ker kes kfa kfc kff kfo kfs kkc kke kkk kkp kkr kks koa koc koe kof kok koo kop kor kos kpa kpc kpe kpf kpk kpo kpp kpr kps kra krc krf krk kro krp krr krs ksa ksc kse ksf ksk kso ksp ksr kss oaa oac oae oaf oak oao oap oar oas oc- oca occ ocf ock oco ocp ocr ocs oea oec oee oef oeo oep oer oes of- ofa ofc ofe off ofo ofp ofr ofs oka okc oke okk oko okp okr oks oo- ooa ooc oof ook ooo oop oor oos op- opa opc ope opf opk opo opp opr ops or- ora orc ore orf ork oro orp orr ors os- osa osc ose osf osk oso osp osr oss p-p paa pac pae paf pak pao pap par pas pca pcc pce pcf pck pco pcp pcr pcs pea pec pee pef pek peo pep per pes pfa pfc pfe pff pfk pfo pfp pfr pfs pka pkc pke pkf pko pkp pkr pks poa poc poe pof pok poo pop por pos ppa ppc ppe ppf ppk ppo ppp ppr pps pra prc pre prf prk pro prp prr prs ps- psa psc pse psf psk pso psp psr pss ra- raa rac rae raf rak rao rap rar ras rca rcc rce rcf rco rcp rcr rcs re- rea rec ree ref rek reo rep rer res rfa rfc rfe rff rfk rfo rfp rfr rfs rkc rke rkf rkk rko rkp rks roa roc roe rof rok roo rop ror ros rpa rpc rpe rpf rpk rpo rpp rpr rps rra rrc rrf rrk rrp rrr rrs rsa rsc rse rsf rsk rso rsp rsr rss saa sac sae saf sak sao sap sar sas sca scc sce scf sck sco scp scr scs se- sea sec see sef sek seo sep ser ses sfa sfc sfe sff sfk sfo sfp sfr sfs sk- ska skc ske skf skk sko skp skr sks soa soc soe sof sok soo sop sor sos spa spc spe spf spk spo spp spr sps sr- sra src sre srf srk sro srp srr srs ss- ssa ssc sse ssf ssk sso ssp ssr sss