a-a a-b a-t aaa aab aag aak aao aar aat ab- aba abb abg abk abo abr abt ag- aga agb agg agk ago agr agt aka akb akg akk ako akr aoa aob aog aok aoo aor aot ar- ara arb arg ark aro arr art at- ata atb atg ato atr att baa bab bag bak bao bar bat bba bbb bbg bbk bbo bbr bbt bga bgb bgg bgk bgo bgr bgt bka bkb bkg bkk bko bkr bkt boa bob bog bok boo bor bot bra brb brg brk bro brr brt bta btb btg btk bto btr btt gaa gab gag gak gao gar gat gba gbg gbk gbo gbr gbt gga ggb ggg ggo ggr ggt gka gkb gko gkt goa gob gog gok goo gor got gra grb grg grk gro grr grt gta gtb gtg gtk gto gtr gtt k-t ka- kaa kab kag kak kao kar kat kba kbb kbk kbo kbr kga kgb kgo kkb kkk kkr kkt koa kob kog kok koo kor kot kra krg krk kro krr krt kta ktb ktg ktk kto ktr ktt oaa oab oag oak oao oar oat ob- oba obb obg obk obo obr obt oga ogg ogo ogt oka okb okg okk oko okr oo- ooa oob oog ook ooo oor oot or- ora orb org ork oro orr ort ot- ota otb otg otk oto otr ott ra- raa rab rag rak rao rar rat rba rbb rbg rbk rbo rbr rbt rga rgb rgg rgk rgo rgr rgt rkb rkg rkk rko rkt roa rob rog rok roo ror rot rra rrb rrg rrk rrr rrt rta rtb rtg rtk rto rtr rtt taa tab tag tak tao tar tat tba tbb tbg tbk tbo tbr tbt tga tgb tgg tgk tgo tgr tgt tka tkb tkg tkk tko tkr tkt to- toa tob tog tok too tor tot tra trb trg trk tro trr trt tta ttb ttg ttk tto ttr ttt