-er a-a a-c aaa aac aae aan aar aas aax ac- aca acc ace acn acr acs acx aea aec aee aen aer aes aex an- ana anc ane ann anr ans anx ar- ara arc are arn arr ars arx as- asa asc ase asn asr ass asx ax- axa axe axn axr axs axx c-- caa cac cae can car cas cax cca ccc cce ccn ccr ccs ccx ce- cea cec cee cen cer ces cex cn- cna cnc cne cnn cnr cns cnx cra crc cre crn crr crs crx csa csc cse csn csr css csx cxc cxr cxs cxx eaa eac eae ean ear eas eax ec- eca ecc ece ecn ecr ecs ecx eea eec eee een eer ees eex en- ena enc ene enn enr ens era erc ere ern err ers es- esa esc ese esn esr ess esx ex- exa exc exe exr exs exx naa nac nae nan nar nas nax nca ncc nce ncn ncr ncs ncx ne- nea nec nee nen ner nes nex nna nnc nne nnn nns nra nrc nre nrn nrr nrs nrx nsa nsc nse nsn nsr nss nsx nxc ra- raa rac rae ran rar ras rax rca rcc rce rcn rcr rcs rcx re- rea rec ree ren rer res rex rna rnc rnn rnr rns rra rrc rrn rrr rrs rsa rsc rse rsn rsr rss rsx rxr rxs saa sac sae san sar sas sax sca scc sce scn scr scs scx se- sea sec see sen ser ses sex sna snc sne snn snr sns sr- sra src sre srn srr srs srx ss- ssa ssc sse ssn ssr sss ssx sxc sxn sxs xaa xac xan xar xas xcr xcx xee xen xer xes xex xna xnc xns xrc xrx xsa xsc xss xxx