-er a-a a-b a-c a-t aaa aab aac aae aak aan aar aas aat ab- aba abb abc abe abk abn abr abs abt ac- aca acb acc ace ack acn acr acs act aea aeb aec aee aek aen aer aes aet aka akb akc ake akk akn akr aks an- ana anb anc ane ank ann anr ans ant ar- ara arb arc are ark arn arr ars art as- asa asb asc ase ask asn asr ass ast at- ata atb atc ate atn atr ats att baa bab bac bae bak ban bar bas bat bba bbb bbc bbe bbk bbn bbr bbs bbt bca bcb bcc bce bck bcn bcr bcs bct be- bea beb bec bee bek ben ber bes bet bka bkb bkc bke bkk bkn bkr bks bkt bna bnb bnc bne bnk bnn bnr bns bnt bra brb bre brk brn brr brs brt bsa bsb bsc bse bsk bsn bsr bss bst bta btb btc bte btk btn btr bts btt c-- caa cab cac cae cak can car cas cat cba cbb cbc cbe cbk cbn cbr cbs cbt cca ccb ccc cce cck ccn ccr ccs cct ce- cea ceb cec cee cek cen cer ces cet cka ckb ckc cks ckt cn- cna cnb cnc cne cnn cnr cns cnt cra crb crc cre crk crn crr crs crt csa csb csc cse csk csn csr css cst cta ctb ctc cte ctk ctn ctr cts ctt eaa eab eac eae eak ean ear eas eat eba ebb ebc ebe ebk ebn ebr ebs ebt ec- eca ecb ecc ece eck ecn ecr ecs ect eea eeb eec eee eek een eer ees eet eka ekb ekc eke ekr eks ekt en- ena enb enc ene enk enn enr ens ent era erb erc ere erk ern err ers ert es- esa esb esc ese esk esn esr ess est eta etb etc ete etk etn etr ets ett k-t ka- kaa kab kac kae kak kan kar kas kat kba kbb kbc kbe kbk kbn kbr kbs kca kcb kcc kce kck kcn kcr kcs kct ke- kea keb kec kee kek ken ker kes ket kkb kkc kke kkk kkn kkr kks kkt kn- kna knc kne knk knn knr knt kra krc krk krn krr krs krt ksa ksb ksc kse ksk ksn ksr kss kst kta ktb ktc kte ktk ktn ktr kts ktt naa nab nac nae nak nan nar nas nat nba nbb nbc nbe nbk nbn nbr nbs nbt nca ncb ncc nce nck ncn ncr ncs nct ne- nea neb nec nee nek nen ner nes net nka nkc nke nkk nkn nkr nks nkt nna nnb nnc nne nnk nnn nns nnt nra nrb nrc nre nrk nrn nrr nrs nrt nsa nsb nsc nse nsk nsn nsr nss nst nta ntb ntc nte ntk ntn ntr nts ntt ra- raa rab rac rae rak ran rar ras rat rba rbb rbc rbe rbk rbn rbr rbs rbt rca rcb rcc rce rcn rcr rcs rct re- rea reb rec ree rek ren rer res ret rkb rkc rke rkk rks rkt rna rnb rnc rnn rnr rns rnt rra rrb rrc rrk rrn rrr rrs rrt rsa rsb rsc rse rsk rsn rsr rss rst rta rtb rtc rte rtk rtn rtr rts rtt saa sab sac sae sak san sar sas sat sba sbb sbc sbe sbk sbn sbr sbs sbt sca scb scc sce sck scn scr scs sct se- sea seb sec see sek sen ser ses set sk- ska skb skc ske skk skr sks skt sna snb snc sne snk snn snr sns snt sr- sra srb src sre srk srn srr srs srt ss- ssa ssb ssc sse ssk ssn ssr sss sst sta stb stc ste stk stn str sts stt taa tab tac tae tak tan tar tas tat tba tbb tbc tbe tbk tbn tbr tbs tbt tca tcb tcc tce tck tcn tcr tcs tct te- tea teb tec tee tek ten ter tes tet tka tkb tkc tke tkk tkr tks tkt tna tnb tnc tne tnk tnn tnr tns tnt tra trb trc tre trk trn trr trs trt tsa tsb tsc tse tsk tsn tsr tss tst tta ttb ttc tte ttk ttn ttr tts ttt