a-a a-b a-t aaa aab aan aao aat aau ab- aba abb abn abo abt abu an- ana anb ann ano ant anu aoa aob aon aoo aot aou at- ata atb atn ato att atu au- aua aub aun auo aut b-u baa bab ban bao bat bau bba bbb bbn bbo bbt bbu bna bnb bnn bno bnt bnu boa bob bon boo bot bou bta btb btn bto btt btu bua bub bun buo but buu naa nab nan nao nat nau nba nbb nbn nbo nbt nbu nna nnb nnn nno nnt nnu no- noa nob non noo not nou nta ntb ntn nto ntt ntu nua nub nun nuo nut nuu oaa oab oan oao oat oau ob- oba obb obn obo obt obu on- ona onb onn ono ont onu oo- ooa oob oon ooo oot ot- ota otb otn oto ott otu ou- oua oun ouo out taa tab tan tao tat tau tba tbb tbn tbo tbt tbu tna tnb tnn tno tnt to- toa tob ton too tot tou tta ttb ttn tto ttt ttu tua tub tun tuo tut tuu ua- uaa uab uan uao uat uau uba ubb ubn ubo ubt ubu un- una unb unn uno unt unu uoa uob uon uoo uot uta utb utn uto utt utu uua uun uut uuu