-er a-a a-c aaa aac aae aak aam aao aar ac- aca acc ace ack acm aco acr aea aec aee aek aem aeo aer aka akc ake akk akm ako akr ama amc ame amk amm amo amr aoa aoc aoe aok aom aoo aor ar- ara arc are ark arm aro arr c-- caa cac cae cak cam cao car cca ccc cce cck ccm cco ccr ce- cea cec cee cek cem ceo cer cka ckc ckm cko cma cmc cme cmk cmm cmo cmr co- coa coc coe cok com coo cor cra crc cre crk crm cro crr eaa eac eae eak eam eao ear ec- eca ecc ece eck ecm eco ecr eea eec eee eek eem eeo eer eka ekc eke eko ekr em- ema emc eme emk emm emo emr eo- eoa eoc eoe eok eom eoo eor era erc ere erk erm ero err ka- kaa kac kae kak kam kao kar kca kcc kce kck kcm kcr ke- kea kec kee kek kem keo ker kkc kke kkk kkm kkr kma kmc kme kmk kmm kmo koa koc koe kok kom koo kor kra krc krk kro krr m-o m-r maa mac mae mak mam mao mar mc- mca mcc mce mck mcm mco mcr mea mec mee mek mem meo mer mka mkc mke mkk mkm mko mkr mma mmc mme mmk mmm mmo mmr moa moc moe mok mom moo mor mra mrc mre mrk mrm mro mrr oaa oac oae oak oam oao oar oc- oca occ ock ocm oco ocr oea oec oee oem oeo oer oka okc oke okk oko okr om- oma omc ome omm omo omr oo- ooa ooc ook oom ooo oor or- ora orc ore ork orm oro orr ra- raa rac rae rak ram rao rar rca rcc rce rcm rco rcr re- rea rec ree rek rem reo rer rkc rke rkk rkm rko rma rmc rme rmm rmo rmr roa roc roe rok rom roo ror rra rrc rrk rrm rrr