a-a a-b a-t aaa aab aag aao aar aas aat ab- aba abb abg abo abr abs abt ag- aga agb agg ago agr ags agt aoa aob aog aoo aor aos aot ar- ara arb arg aro arr ars art as- asa asb asg aso asr ass ast at- ata atb atg ato atr ats att baa bab bag bao bar bas bat bba bbb bbg bbo bbr bbs bbt bga bgb bgg bgo bgr bgs bgt boa bob bog boo bor bos bot bra brb brg bro brr brs brt bsa bsb bsg bso bsr bss bst bta btb btg bto btr bts btt gaa gab gag gao gar gas gat gba gbg gbo gbr gbs gbt gga ggb ggg ggo ggr ggs ggt goa gob gog goo gor gos got gra grb grg gro grr grs grt gsa gsb gsg gso gsr gss gst gta gtb gtg gto gtr gts gtt oaa oab oag oao oar oas oat ob- oba obb obg obo obr obs obt oga ogg ogo ogs ogt oo- ooa oob oog ooo oor oos oot or- ora orb org oro orr ors ort os- osa osb osg oso osr oss ost ot- ota otb otg oto otr ots ott ra- raa rab rag rao rar ras rat rba rbb rbg rbo rbr rbs rbt rga rgb rgg rgo rgr rgs rgt roa rob rog roo ror ros rot rra rrb rrg rrr rrs rrt rsa rsb rsg rso rsr rss rst rta rtb rtg rto rtr rts rtt saa sab sag sao sar sas sat sba sbb sbg sbo sbr sbs sbt sga sgb sgg sgo sgr sgs sgt soa sob sog soo sor sos sot sr- sra srb srg sro srr srs srt ss- ssa ssb ssg sso ssr sss sst sta stb stg sto str sts stt taa tab tag tao tar tas tat tba tbb tbg tbo tbr tbs tbt tga tgb tgg tgo tgr tgs tgt to- toa tob tog too tor tos tot tra trb trg tro trr trs trt tsa tsb tsg tso tsr tss tst tta ttb ttg tto ttr tts ttt