a-a a-b a-t aaa aab aag aan aar aat ab- aba abb abg abn abr abt ag- aga agb agg agn agr agt an- ana anb ang ann anr ant ar- ara arb arg arn arr art at- ata atb atg atn atr att baa bab bag ban bar bat bba bbb bbg bbn bbr bbt bga bgb bgg bgn bgr bgt bna bnb bng bnn bnr bnt bra brb brg brn brr brt bta btb btg btn btr btt gaa gab gag gan gar gat gba gbg gbn gbr gbt gga ggb ggg ggn ggr ggt gna gnb gnn gnr gnt gra grb grg grn grr grt gta gtb gtg gtn gtr gtt naa nab nag nan nar nat nba nbb nbg nbn nbr nbt nga ngb ngg ngn ngt nna nnb nng nnn nnt nra nrb nrg nrn nrr nrt nta ntb ntg ntn ntr ntt ra- raa rab rag ran rar rat rba rbb rbg rbn rbr rbt rga rgb rgg rgn rgr rgt rna rnb rng rnn rnr rnt rra rrb rrg rrn rrr rrt rta rtb rtg rtn rtr rtt taa tab tag tan tar tat tba tbb tbg tbn tbr tbt tga tgb tgg tgn tgr tgt tna tnb tng tnn tnr tnt tra trb trg trn trr trt tta ttb ttg ttn ttr ttt