a-a a-b a-t aaa aab aag aan aao aar aat ab- aba abb abg abn abo abr abt ag- aga agb agg agn ago agr agt an- ana anb ang ann ano anr ant aoa aob aog aon aoo aor aot ar- ara arb arg arn aro arr art at- ata atb atg atn ato atr att baa bab bag ban bao bar bat bba bbb bbg bbn bbo bbr bbt bga bgb bgg bgn bgo bgr bgt bna bnb bng bnn bno bnr bnt boa bob bog bon boo bor bot bra brb brg brn bro brr brt bta btb btg btn bto btr btt gaa gab gag gan gao gar gat gba gbg gbn gbo gbr gbt gga ggb ggg ggn ggo ggr ggt gna gnb gnn gno gnr gnt goa gob gog gon goo gor got gra grb grg grn gro grr grt gta gtb gtg gtn gto gtr gtt naa nab nag nan nao nar nat nba nbb nbg nbn nbo nbr nbt nga ngb ngg ngn ngo ngt nna nnb nng nnn nno nnt no- noa nob nog non noo nor not nra nrb nrg nrn nro nrr nrt nta ntb ntg ntn nto ntr ntt oaa oab oag oan oao oar oat ob- oba obb obg obn obo obr obt oga ogg ogn ogo ogt on- ona onb ong onn ono onr ont oo- ooa oob oog oon ooo oor oot or- ora orb org orn oro orr ort ot- ota otb otg otn oto otr ott ra- raa rab rag ran rao rar rat rba rbb rbg rbn rbo rbr rbt rga rgb rgg rgn rgo rgr rgt rna rnb rng rnn rno rnr rnt roa rob rog ron roo ror rot rra rrb rrg rrn rrr rrt rta rtb rtg rtn rto rtr rtt taa tab tag tan tao tar tat tba tbb tbg tbn tbo tbr tbt tga tgb tgg tgn tgo tgr tgt tna tnb tng tnn tno tnr tnt to- toa tob tog ton too tor tot tra trb trg trn tro trr trt tta ttb ttg ttn tto ttr ttt