a-a a-b a-t aaa aab aaf aak aan aao aat ab- aba abb abf abk abn abo abt af- afa afb aff afk afn afo aft aka akb akk akn ako an- ana anb anf ank ann ano ant aoa aob aof aok aon aoo aot at- ata atb atf atn ato att baa bab baf bak ban bao bat bba bbb bbf bbk bbn bbo bbt bfa bfb bff bfn bfo bft bka bkb bkf bkk bkn bko bkt bna bnb bnf bnk bnn bno bnt boa bob bof bok bon boo bot bta btb btf btk btn bto btt faa fab faf fak fan fao fat fba fbb fbf fbk fbn fbo fbt ffa fff ffk ffn ffo fft fka fkb fkf fkk fkt fna fnb fnf fnk fnn fnt foa fob fof fok fon foo fot fta ftb ftf ftk ftn fto ftt k-t ka- kaa kab kaf kak kan kao kat kba kbb kbf kbk kbn kbo kfa kff kfo kkb kkk kkn kkt kn- kna knf knk knn kno knt koa kob kof kok kon koo kot kta ktb ktf ktk ktn kto ktt naa nab naf nak nan nao nat nba nbb nbf nbk nbn nbo nbt nfa nfb nff nfk nfn nfo nft nka nkf nkk nkn nko nkt nna nnb nnf nnk nnn nno nnt no- noa nob nof nok non noo not nta ntb ntf ntk ntn nto ntt oaa oab oaf oak oan oao oat ob- oba obb obf obk obn obo obt of- ofa ofb off ofn ofo oft oka okb okk oko on- ona onb onf onk onn ono ont oo- ooa oob oof ook oon ooo oot ot- ota otb otf otk otn oto ott taa tab taf tak tan tao tat tba tbb tbf tbk tbn tbo tbt tfa tfb tff tfk tfn tfo tft tka tkb tkk tko tkt tna tnb tnf tnk tnn tno tnt to- toa tob tof tok ton too tot tta ttb ttf ttk ttn tto ttt