-er a-a a-c aaa aac aae aaf aag aak aao aar aas ac- aca acc ace acf acg ack aco acr acs aea aec aee aef aeg aek aeo aer aes af- afa afc afe aff afg afk afo afr afs ag- aga agc age agf agg agk ago agr ags aka akc ake akg akk ako akr aks aoa aoc aoe aof aog aok aoo aor aos ar- ara arc are arf arg ark aro arr ars as- asa asc ase asf asg ask aso asr ass c-- caa cac cae caf cag cak cao car cas cca ccc cce ccf ccg cck cco ccr ccs ce- cea cec cee cef ceg cek ceo cer ces cfa cfc cfe cff cfg cfk cfo cfr cfs cga cgc cge cgg cgo cgr cgs cka ckc cko cks co- coa coc coe cof cog cok coo cor cos cra crc cre crf crg crk cro crr crs csa csc cse csf csg csk cso csr css eaa eac eae eaf eag eak eao ear eas ec- eca ecc ece ecf ecg eck eco ecr ecs eea eec eee eef eeg eek eeo eer ees ef- efa efc efe eff efg efo efr efs ega egc ege egf egg ego egr egs eka ekc eke ekf ekg eko ekr eks eo- eoa eoc eoe eof eog eok eoo eor eos era erc ere erf erg erk ero err ers es- esa esc ese esf esg esk eso esr ess faa fac fae faf fag fak fao far fas fca fcc fce fcf fcg fck fco fcr fcs fea fec fee fef feg fek feo fer fes ffa ffc ffe fff ffg ffk ffo ffr ffs fga fgc fge fgf fgg fgr fgs fka fkc fkf fkg fkk foa foc foe fof fog fok foo for fos fra frc fre frf frg frk fro frr frs fsa fsc fse fsf fsg fsk fso fsr fss gaa gac gae gaf gag gak gao gar gas gca gcc gce gcf gcg gck gco gcr gcs ge- gea gec gee gef geg gek geo ger ges gfa gfc gfe gff gfk gfo gfr gfs gga ggc ggg ggo ggr ggs gka gko gks goa goc goe gof gog gok goo gor gos gra grc gre grf grg grk gro grr grs gsa gsc gse gsf gsg gsk gso gsr gss ka- kaa kac kae kaf kag kak kao kar kas kca kcc kce kcg kck kcr kcs ke- kea kec kee kef keg kek keo ker kes kfa kfc kff kfg kfo kfs kga kgc kgf kgo kgs kkc kke kkk kkr kks koa koc koe kof kog kok koo kor kos kra krc krf krg krk kro krr krs ksa ksc kse ksf ksg ksk kso ksr kss oaa oac oae oaf oag oak oao oar oas oc- oca occ ocf ocg ock oco ocr ocs oea oec oee oef oeg oeo oer oes of- ofa ofc ofe off ofg ofo ofr ofs oga ogc oge ogf ogg ogo ogs oka okc oke okg okk oko okr oks oo- ooa ooc oof oog ook ooo oor oos or- ora orc ore orf org ork oro orr ors os- osa osc ose osf osg osk oso osr oss ra- raa rac rae raf rag rak rao rar ras rca rcc rce rcf rcg rco rcr rcs re- rea rec ree ref reg rek reo rer res rfa rfc rfe rff rfg rfk rfo rfr rfs rga rgc rge rgf rgg rgk rgo rgr rgs rkc rke rkf rkg rkk rko rks roa roc roe rof rog rok roo ror ros rra rrc rrf rrg rrk rrr rrs rsa rsc rse rsf rsg rsk rso rsr rss saa sac sae saf sag sak sao sar sas sca scc sce scf scg sck sco scr scs se- sea sec see sef seg sek seo ser ses sfa sfc sfe sff sfg sfk sfo sfr sfs sga sgc sge sgf sgg sgk sgo sgr sgs sk- ska skc ske skf skg skk sko skr sks soa soc soe sof sog sok soo sor sos sr- sra src sre srf srg srk sro srr srs ss- ssa ssc sse ssf ssg ssk sso ssr sss