a-a a-b a-i a-t aaa aab aag aai aar aas aat ab- aba abb abg abi abr abs abt ag- aga agb agg agi agr ags agt ai- aia aib aig aii air ais ait ar- ara arb arg ari arr ars art as- asa asb asg asi asr ass ast at- ata atb atg ati atr ats att baa bab bag bai bar bas bat bba bbb bbg bbi bbr bbs bbt bga bgb bgg bgi bgr bgs bgt bi- bia bib big bii bir bis bit bra brb brg bri brr brs brt bsa bsb bsg bsi bsr bss bst bta btb btg bti btr bts btt gaa gab gag gai gar gas gat gba gbg gbi gbr gbs gbt gga ggb ggg ggi ggr ggs ggt gia gib gig gii gir gis git gra grb grg gri grr grs grt gsa gsb gsg gsi gsr gss gst gta gtb gtg gti gtr gts gtt ia- iaa iab iag iai iar ias iat iba ibb ibg ibi ibr ibs ibt iga igb igg igi igr igs igt iia iib iii iir iis iit ir- ira irb irg iri irr irs irt is- isa isb isg isi isr iss ist ita itb itg iti its itt ra- raa rab rag rai rar ras rat rba rbb rbg rbi rbr rbs rbt rga rgb rgg rgi rgr rgs rgt ria rib rig rii rir ris rit rra rrb rrg rri rrr rrs rrt rsa rsb rsg rsi rsr rss rst rta rtb rtg rti rtr rts rtt saa sab sag sai sar sas sat sba sbb sbg sbi sbr sbs sbt sga sgb sgg sgi sgr sgs sgt sia sib sig sii sir sis sit sr- sra srb srg sri srr srs srt ss- ssa ssb ssg ssi ssr sss sst sta stb stg sti str sts stt taa tab tag tai tar tas tat tba tbb tbg tbi tbr tbs tbt tga tgb tgg tgi tgr tgs tgt tia tib tig tii tir tis tit tra trb trg tri trr trs trt tsa tsb tsg tsi tsr tss tst tta ttb ttg tti ttr tts ttt