-er a-a a-c a-t aaa aac aae aan aar aat aax ac- aca acc ace acn acr act acx aea aec aee aen aer aet aex an- ana anc ane ann anr ant anx ar- ara arc are arn arr art arx at- ata atc ate atn atr att atx ax- axa axe axn axr axt axx c-- caa cac cae can car cat cax cca ccc cce ccn ccr cct ccx ce- cea cec cee cen cer cet cex cn- cna cnc cne cnn cnr cnt cnx cra crc cre crn crr crt crx cta ctc cte ctn ctr ctt ctx cxc cxr cxt cxx eaa eac eae ean ear eat eax ec- eca ecc ece ecn ecr ect ecx eea eec eee een eer eet eex en- ena enc ene enn enr ent era erc ere ern err ert eta etc ete etn etr ett etx ex- exa exc exe exr ext exx naa nac nae nan nar nat nax nca ncc nce ncn ncr nct ncx ne- nea nec nee nen ner net nex nna nnc nne nnn nnt nra nrc nre nrn nrr nrt nrx nta ntc nte ntn ntr ntt ntx nxc nxt ra- raa rac rae ran rar rat rax rca rcc rce rcn rcr rct rcx re- rea rec ree ren rer ret rex rna rnc rnn rnr rnt rra rrc rrn rrr rrt rta rtc rte rtn rtr rtt rtx rxr t-x taa tac tae tan tar tat tax tca tcc tce tcn tcr tct tcx te- tea tec tee ten ter tet tex tna tnc tne tnn tnr tnt tnx tra trc tre trn trr trt trx tta ttc tte ttn ttr ttt ttx txe txn txt xaa xac xan xar xat xcr xcx xee xen xer xet xex xna xnc xrc xrt xrx xtc xtr xtx xxx