-er a-a a-b a-c a-t aaa aab aac aae aag aar aas aat ab- aba abb abc abe abg abr abs abt ac- aca acb acc ace acg acr acs act aea aeb aec aee aeg aer aes aet ag- aga agb agc age agg agr ags agt ar- ara arb arc are arg arr ars art as- asa asb asc ase asg asr ass ast at- ata atb atc ate atg atr ats att baa bab bac bae bag bar bas bat bba bbb bbc bbe bbg bbr bbs bbt bca bcb bcc bce bcg bcr bcs bct be- bea beb bec bee beg ber bes bet bga bgb bgc bge bgg bgr bgs bgt bra brb bre brg brr brs brt bsa bsb bsc bse bsg bsr bss bst bta btb btc bte btg btr bts btt c-- caa cab cac cae cag car cas cat cba cbb cbc cbe cbg cbr cbs cbt cca ccb ccc cce ccg ccr ccs cct ce- cea ceb cec cee ceg cer ces cet cga cgb cgc cge cgg cgr cgs cgt cra crb crc cre crg crr crs crt csa csb csc cse csg csr css cst cta ctb ctc cte ctg ctr cts ctt eaa eab eac eae eag ear eas eat eba ebb ebc ebe ebg ebr ebs ebt ec- eca ecb ecc ece ecg ecr ecs ect eea eeb eec eee eeg eer ees eet ega egb egc ege egg egr egs egt era erb erc ere erg err ers ert es- esa esb esc ese esg esr ess est eta etb etc ete etg etr ets ett gaa gab gac gae gag gar gas gat gba gbc gbe gbg gbr gbs gbt gca gcb gcc gce gcg gcr gcs gct ge- gea geb gec gee geg ger ges get gga ggb ggc ggg ggr ggs ggt gra grb grc gre grg grr grs grt gsa gsb gsc gse gsg gsr gss gst gta gtb gtc gte gtg gtr gts gtt ra- raa rab rac rae rag rar ras rat rba rbb rbc rbe rbg rbr rbs rbt rca rcb rcc rce rcg rcr rcs rct re- rea reb rec ree reg rer res ret rga rgb rgc rge rgg rgr rgs rgt rra rrb rrc rrg rrr rrs rrt rsa rsb rsc rse rsg rsr rss rst rta rtb rtc rte rtg rtr rts rtt saa sab sac sae sag sar sas sat sba sbb sbc sbe sbg sbr sbs sbt sca scb scc sce scg scr scs sct se- sea seb sec see seg ser ses set sga sgb sgc sge sgg sgr sgs sgt sr- sra srb src sre srg srr srs srt ss- ssa ssb ssc sse ssg ssr sss sst sta stb stc ste stg str sts stt taa tab tac tae tag tar tas tat tba tbb tbc tbe tbg tbr tbs tbt tca tcb tcc tce tcg tcr tcs tct te- tea teb tec tee teg ter tes tet tga tgb tgc tge tgg tgr tgs tgt tra trb trc tre trg trr trs trt tsa tsb tsc tse tsg tsr tss tst tta ttb ttc tte ttg ttr tts ttt