a-a a-b a-c a-t aaa aab aac aak aan aao aat ab- aba abb abc abk abn abo abt ac- aca acb acc ack acn aco act aka akb akc akk akn ako an- ana anb anc ank ann ano ant aoa aob aoc aok aon aoo aot at- ata atb atc atn ato att baa bab bac bak ban bao bat bba bbb bbc bbk bbn bbo bbt bca bcb bcc bck bcn bco bct bka bkb bkc bkk bkn bko bkt bna bnb bnc bnk bnn bno bnt boa bob boc bok bon boo bot bta btb btc btk btn bto btt c-- caa cab cac cak can cao cat cba cbb cbc cbk cbn cbo cbt cca ccb ccc cck ccn cco cct cka ckb ckc cko ckt cn- cna cnb cnc cnn cno cnt co- coa cob coc cok con coo cot cta ctb ctc ctk ctn cto ctt k-t ka- kaa kab kac kak kan kao kat kba kbb kbc kbk kbn kbo kca kcb kcc kck kcn kct kkb kkc kkk kkn kkt kn- kna knc knk knn kno knt koa kob koc kok kon koo kot kta ktb ktc ktk ktn kto ktt naa nab nac nak nan nao nat nba nbb nbc nbk nbn nbo nbt nca ncb ncc nck ncn nco nct nka nkc nkk nkn nko nkt nna nnb nnc nnk nnn nno nnt no- noa nob noc nok non noo not nta ntb ntc ntk ntn nto ntt oaa oab oac oak oan oao oat ob- oba obb obc obk obn obo obt oc- oca ocb occ ock ocn oco oct oka okb okc okk oko on- ona onb onc onk onn ono ont oo- ooa oob ooc ook oon ooo oot ot- ota otb otc otk otn oto ott taa tab tac tak tan tao tat tba tbb tbc tbk tbn tbo tbt tca tcb tcc tck tcn tco tct tka tkb tkc tkk tko tkt tna tnb tnc tnk tnn tno tnt to- toa tob toc tok ton too tot tta ttb ttc ttk ttn tto ttt