-er a-a a-b a-c a-t aaa aab aac aae aag aak aar aas aat ab- aba abb abc abe abg abk abr abs abt ac- aca acb acc ace acg ack acr acs act aea aeb aec aee aeg aek aer aes aet ag- aga agb agc age agg agk agr ags agt aka akb akc ake akg akk akr aks ar- ara arb arc are arg ark arr ars art as- asa asb asc ase asg ask asr ass ast at- ata atb atc ate atg atr ats att baa bab bac bae bag bak bar bas bat bba bbb bbc bbe bbg bbk bbr bbs bbt bca bcb bcc bce bcg bck bcr bcs bct be- bea beb bec bee beg bek ber bes bet bga bgb bgc bge bgg bgk bgr bgs bgt bka bkb bkc bke bkg bkk bkr bks bkt bra brb bre brg brk brr brs brt bsa bsb bsc bse bsg bsk bsr bss bst bta btb btc bte btg btk btr bts btt c-- caa cab cac cae cag cak car cas cat cba cbb cbc cbe cbg cbk cbr cbs cbt cca ccb ccc cce ccg cck ccr ccs cct ce- cea ceb cec cee ceg cek cer ces cet cga cgb cgc cge cgg cgr cgs cgt cka ckb ckc cks ckt cra crb crc cre crg crk crr crs crt csa csb csc cse csg csk csr css cst cta ctb ctc cte ctg ctk ctr cts ctt eaa eab eac eae eag eak ear eas eat eba ebb ebc ebe ebg ebk ebr ebs ebt ec- eca ecb ecc ece ecg eck ecr ecs ect eea eeb eec eee eeg eek eer ees eet ega egb egc ege egg egr egs egt eka ekb ekc eke ekg ekr eks ekt era erb erc ere erg erk err ers ert es- esa esb esc ese esg esk esr ess est eta etb etc ete etg etk etr ets ett gaa gab gac gae gag gak gar gas gat gba gbc gbe gbg gbk gbr gbs gbt gca gcb gcc gce gcg gck gcr gcs gct ge- gea geb gec gee geg gek ger ges get gga ggb ggc ggg ggr ggs ggt gka gkb gks gkt gra grb grc gre grg grk grr grs grt gsa gsb gsc gse gsg gsk gsr gss gst gta gtb gtc gte gtg gtk gtr gts gtt k-t ka- kaa kab kac kae kag kak kar kas kat kba kbb kbc kbe kbk kbr kbs kca kcb kcc kce kcg kck kcr kcs kct ke- kea keb kec kee keg kek ker kes ket kga kgb kgc kgs kkb kkc kke kkk kkr kks kkt kra krc krg krk krr krs krt ksa ksb ksc kse ksg ksk ksr kss kst kta ktb ktc kte ktg ktk ktr kts ktt ra- raa rab rac rae rag rak rar ras rat rba rbb rbc rbe rbg rbk rbr rbs rbt rca rcb rcc rce rcg rcr rcs rct re- rea reb rec ree reg rek rer res ret rga rgb rgc rge rgg rgk rgr rgs rgt rkb rkc rke rkg rkk rks rkt rra rrb rrc rrg rrk rrr rrs rrt rsa rsb rsc rse rsg rsk rsr rss rst rta rtb rtc rte rtg rtk rtr rts rtt saa sab sac sae sag sak sar sas sat sba sbb sbc sbe sbg sbk sbr sbs sbt sca scb scc sce scg sck scr scs sct se- sea seb sec see seg sek ser ses set sga sgb sgc sge sgg sgk sgr sgs sgt sk- ska skb skc ske skg skk skr sks skt sr- sra srb src sre srg srk srr srs srt ss- ssa ssb ssc sse ssg ssk ssr sss sst sta stb stc ste stg stk str sts stt taa tab tac tae tag tak tar tas tat tba tbb tbc tbe tbg tbk tbr tbs tbt tca tcb tcc tce tcg tck tcr tcs tct te- tea teb tec tee teg tek ter tes tet tga tgb tgc tge tgg tgk tgr tgs tgt tka tkb tkc tke tkg tkk tkr tks tkt tra trb trc tre trg trk trr trs trt tsa tsb tsc tse tsg tsk tsr tss tst tta ttb ttc tte ttg ttk ttr tts ttt