-er a-a a-c aaa aac aae aaf aag aak aao aap aar ac- aca acc ace acf acg ack aco acp acr aea aec aee aef aeg aek aeo aep aer af- afa afc afe aff afg afk afo afp afr ag- aga agc age agf agg agk ago agp agr aka akc ake akg akk ako akp akr aoa aoc aoe aof aog aok aoo aop aor ap- apa apc ape apf apg apk apo app apr ar- ara arc are arf arg ark aro arp arr c-- caa cac cae caf cag cak cao cap car cca ccc cce ccf ccg cck cco ccp ccr ce- cea cec cee cef ceg cek ceo cep cer cfa cfc cfe cff cfg cfk cfo cfp cfr cga cgc cge cgg cgo cgp cgr cka ckc cko co- coa coc coe cof cog cok coo cop cor cpa cpc cpe cpf cpg cpk cpo cpp cpr cra crc cre crf crg crk cro crp crr eaa eac eae eaf eag eak eao eap ear ec- eca ecc ece ecf ecg eck eco ecr eea eec eee eef eeg eek eeo eep eer ef- efa efc efe eff efg efo efp efr ega egc ege egf egg ego egp egr eka ekc eke ekf ekg eko ekp ekr eo- eoa eoc eoe eof eog eok eoo eop eor ep- epa epc epe epf epg epo epp epr era erc ere erf erg erk ero erp err faa fac fae faf fag fak fao fap far fca fcc fce fcf fcg fck fco fcp fcr fea fec fee fef feg fek feo fep fer ffa ffc ffe fff ffg ffk ffo ffp ffr fga fgc fge fgf fgg fgp fgr fka fkc fkf fkg fkk fkp foa foc foe fof fog fok foo fop for fpa fpc fpe fpg fpk fpo fpp fpr fra frc fre frf frg frk fro frp frr g-p gaa gac gae gaf gag gak gao gap gar gca gcc gce gcf gcg gck gco gcp gcr ge- gea gec gee gef geg gek geo gep ger gfa gfc gfe gff gfk gfo gfp gfr gga ggc ggg ggo ggp ggr gka gko gkp goa goc goe gof gog gok goo gop gor gpa gpc gpe gpf gpg gpk gpo gpp gpr gra grc gre grf grg grk gro grp grr ka- kaa kac kae kaf kag kak kao kap kar kca kcc kce kcg kck kcp kcr ke- kea kec kee kef keg kek keo kep ker kfa kfc kff kfg kfo kga kgc kgf kgo kgp kkc kke kkk kkp kkr koa koc koe kof kog kok koo kop kor kpa kpc kpe kpf kpk kpo kpp kpr kra krc krf krg krk kro krp krr oaa oac oae oaf oag oak oao oap oar oc- oca occ ocf ocg ock oco ocp ocr oea oec oee oef oeg oeo oep oer of- ofa ofc ofe off ofg ofo ofp ofr oga ogc oge ogf ogg ogo ogp oka okc oke okg okk oko okp okr oo- ooa ooc oof oog ook ooo oop oor op- opa opc ope opf opg opk opo opp opr or- ora orc ore orf org ork oro orp orr p-p paa pac pae paf pag pak pao pap par pca pcc pce pcf pcg pck pco pcp pcr pea pec pee pef peg pek peo pep per pfa pfc pfe pff pfg pfk pfo pfp pfr pga pgc pge pgf pgg pgk pgo pgp pgr pka pkc pke pkf pkg pko pkp pkr poa poc poe pof pog pok poo pop por ppa ppc ppe ppf ppg ppk ppo ppp ppr pra prc pre prf prg prk pro prp prr ra- raa rac rae raf rag rak rao rap rar rca rcc rce rcf rcg rco rcp rcr re- rea rec ree ref reg rek reo rep rer rfa rfc rfe rff rfg rfk rfo rfp rfr rga rgc rge rgf rgg rgk rgo rgp rgr rkc rke rkf rkg rkk rko rkp roa roc roe rof rog rok roo rop ror rpa rpc rpe rpf rpg rpk rpo rpp rpr rra rrc rrf rrg rrk rrp rrr