-er a-a a-b a-c a-t aaa aab aac aae aan aar aas aat ab- aba abb abc abe abn abr abs abt ac- aca acb acc ace acn acr acs act aea aeb aec aee aen aer aes aet an- ana anb anc ane ann anr ans ant ar- ara arb arc are arn arr ars art as- asa asb asc ase asn asr ass ast at- ata atb atc ate atn atr ats att baa bab bac bae ban bar bas bat bba bbb bbc bbe bbn bbr bbs bbt bca bcb bcc bce bcn bcr bcs bct be- bea beb bec bee ben ber bes bet bna bnb bnc bne bnn bnr bns bnt bra brb bre brn brr brs brt bsa bsb bsc bse bsn bsr bss bst bta btb btc bte btn btr bts btt c-- caa cab cac cae can car cas cat cba cbb cbc cbe cbn cbr cbs cbt cca ccb ccc cce ccn ccr ccs cct ce- cea ceb cec cee cen cer ces cet cn- cna cnb cnc cne cnn cnr cns cnt cra crb crc cre crn crr crs crt csa csb csc cse csn csr css cst cta ctb ctc cte ctn ctr cts ctt eaa eab eac eae ean ear eas eat eba ebb ebc ebe ebn ebr ebs ebt ec- eca ecb ecc ece ecn ecr ecs ect eea eeb eec eee een eer ees eet en- ena enb enc ene enn enr ens ent era erb erc ere ern err ers ert es- esa esb esc ese esn esr ess est eta etb etc ete etn etr ets ett naa nab nac nae nan nar nas nat nba nbb nbc nbe nbn nbr nbs nbt nca ncb ncc nce ncn ncr ncs nct ne- nea neb nec nee nen ner nes net nna nnb nnc nne nnn nns nnt nra nrb nrc nre nrn nrr nrs nrt nsa nsb nsc nse nsn nsr nss nst nta ntb ntc nte ntn ntr nts ntt ra- raa rab rac rae ran rar ras rat rba rbb rbc rbe rbn rbr rbs rbt rca rcb rcc rce rcn rcr rcs rct re- rea reb rec ree ren rer res ret rna rnb rnc rnn rnr rns rnt rra rrb rrc rrn rrr rrs rrt rsa rsb rsc rse rsn rsr rss rst rta rtb rtc rte rtn rtr rts rtt saa sab sac sae san sar sas sat sba sbb sbc sbe sbn sbr sbs sbt sca scb scc sce scn scr scs sct se- sea seb sec see sen ser ses set sna snb snc sne snn snr sns snt sr- sra srb src sre srn srr srs srt ss- ssa ssb ssc sse ssn ssr sss sst sta stb stc ste stn str sts stt taa tab tac tae tan tar tas tat tba tbb tbc tbe tbn tbr tbs tbt tca tcb tcc tce tcn tcr tcs tct te- tea teb tec tee ten ter tes tet tna tnb tnc tne tnn tnr tns tnt tra trb trc tre trn trr trs trt tsa tsb tsc tse tsn tsr tss tst tta ttb ttc tte ttn ttr tts ttt