-er a-a a-c aaa aac aae aam aao aar ac- aca acc ace acm aco acr aea aec aee aem aeo aer ama amc ame amm amo amr aoa aoc aoe aom aoo aor ar- ara arc are arm aro arr c-- caa cac cae cam cao car cca ccc cce ccm cco ccr ce- cea cec cee cem ceo cer cma cmc cme cmm cmo cmr co- coa coc coe com coo cor cra crc cre crm cro crr eaa eac eae eam eao ear ec- eca ecc ece ecm eco ecr eea eec eee eem eeo eer em- ema emc eme emm emo emr eo- eoa eoc eoe eom eoo eor era erc ere erm ero err m-o m-r maa mac mae mam mao mar mc- mca mcc mce mcm mco mcr mea mec mee mem meo mer mma mmc mme mmm mmo mmr moa moc moe mom moo mor mra mrc mre mrm mro mrr oaa oac oae oam oao oar oc- oca occ ocm oco ocr oea oec oee oem oeo oer om- oma omc ome omm omo omr oo- ooa ooc oom ooo oor or- ora orc ore orm oro orr ra- raa rac rae ram rao rar rca rcc rce rcm rco rcr re- rea rec ree rem reo rer rma rmc rme rmm rmo rmr roa roc roe rom roo ror rra rrc rrm rrr