a-a a-b a-c a-t aaa aab aac aan aao aat aau ab- aba abb abc abn abo abt abu ac- aca acb acc acn aco act acu an- ana anb anc ann ano ant anu aoa aob aoc aon aoo aot aou at- ata atb atc atn ato att atu au- aua aub auc aun auo aut b-u baa bab bac ban bao bat bau bba bbb bbc bbn bbo bbt bbu bca bcb bcc bcn bco bct bcu bna bnb bnc bnn bno bnt bnu boa bob boc bon boo bot bou bta btb btc btn bto btt btu bua bub buc bun buo but buu c-- caa cab cac can cao cat cau cba cbb cbc cbn cbo cbt cbu cca ccb ccc ccn cco cct ccu cn- cna cnb cnc cnn cno cnt cnu co- coa cob coc con coo cot cou cta ctb ctc ctn cto ctt ctu cua cub cuc cun cuo cut cuu naa nab nac nan nao nat nau nba nbb nbc nbn nbo nbt nbu nca ncb ncc ncn nco nct ncu nna nnb nnc nnn nno nnt nnu no- noa nob noc non noo not nou nta ntb ntc ntn nto ntt ntu nua nub nuc nun nuo nut nuu oaa oab oac oan oao oat oau ob- oba obb obc obn obo obt obu oc- oca ocb occ ocn oco oct ocu on- ona onb onc onn ono ont onu oo- ooa oob ooc oon ooo oot ot- ota otb otc otn oto ott otu ou- oua ouc oun ouo out taa tab tac tan tao tat tau tba tbb tbc tbn tbo tbt tbu tca tcb tcc tcn tco tct tcu tna tnb tnc tnn tno tnt to- toa tob toc ton too tot tou tta ttb ttc ttn tto ttt ttu tua tub tuc tun tuo tut tuu ua- uaa uab uac uan uao uat uau uba ubb ubc ubn ubo ubt ubu uca ucb ucc ucn uco uct ucu un- una unb unc unn uno unt unu uoa uob uoc uon uoo uot uta utb utc utn uto utt utu uua uuc uun uut uuu