a-a a-b a-t aaa aab aaf aag aan aao aat ab- aba abb abf abg abn abo abt af- afa afb aff afg afn afo aft ag- aga agb agf agg agn ago agt an- ana anb anf ang ann ano ant aoa aob aof aog aon aoo aot at- ata atb atf atg atn ato att baa bab baf bag ban bao bat bba bbb bbf bbg bbn bbo bbt bfa bfb bff bfg bfn bfo bft bga bgb bgf bgg bgn bgo bgt bna bnb bnf bng bnn bno bnt boa bob bof bog bon boo bot bta btb btf btg btn bto btt faa fab faf fag fan fao fat fba fbb fbf fbg fbn fbo fbt ffa fff ffg ffn ffo fft fga fgb fgf fgg fgn fgt fna fnb fnf fng fnn fnt foa fob fof fog fon foo fot fta ftb ftf ftg ftn fto ftt gaa gab gaf gag gan gao gat gba gbf gbg gbn gbo gbt gfa gfb gff gfo gft gga ggb ggg ggn ggo ggt gna gnb gnf gnn gno gnt goa gob gof gog gon goo got gta gtb gtf gtg gtn gto gtt naa nab naf nag nan nao nat nba nbb nbf nbg nbn nbo nbt nfa nfb nff nfn nfo nft nga ngb ngf ngg ngn ngo ngt nna nnb nnf nng nnn nno nnt no- noa nob nof nog non noo not nta ntb ntf ntg ntn nto ntt oaa oab oaf oag oan oao oat ob- oba obb obf obg obn obo obt of- ofa ofb off ofg ofn ofo oft oga ogf ogg ogn ogo ogt on- ona onb onf ong onn ono ont oo- ooa oob oof oog oon ooo oot ot- ota otb otf otg otn oto ott taa tab taf tag tan tao tat tba tbb tbf tbg tbn tbo tbt tfa tfb tff tfg tfn tfo tft tga tgb tgf tgg tgn tgo tgt tna tnb tnf tng tnn tno tnt to- toa tob tof tog ton too tot tta ttb ttf ttg ttn tto ttt