-er a-a a-c aaa aac aae aam aar aax ac- aca acc ace acm acr acx aea aec aee aem aer aex ama amc ame amm amr amx ar- ara arc are arm arr arx ax- axa axe axm axr axx c-- caa cac cae cam car cax cca ccc cce ccm ccr ccx ce- cea cec cee cem cer cex cma cmc cme cmm cmr cmx cra crc cre crm crr crx cxc cxr cxx eaa eac eae eam ear eax ec- eca ecc ece ecm ecr ecx eea eec eee eem eer eex em- ema emc eme emm emr emx era erc ere erm err ex- exa exc exe exr exx m-r maa mac mae mam mar max mc- mca mcc mce mcm mcr mcx mea mec mee mem mer mex mma mmc mme mmm mmr mmx mra mrc mre mrm mrr mrx mxa mxc mxr ra- raa rac rae ram rar rax rca rcc rce rcm rcr rcx re- rea rec ree rem rer rex rma rmc rme rmm rmr rmx rra rrc rrm rrr rxr xaa xac xam xar xcr xcx xee xem xer xex xma xmc xmm xmr xmx xrc xrx xxx