b-u bbb bbc bbk bbn bbo bbt bbu bcb bcc bck bcn bco bct bcu bkb bkc bkk bkn bko bkt bnb bnc bnk bnn bno bnt bnu bob boc bok bon boo bot bou btb btc btk btn bto btt btu bub buc buk bun buo but buu c-- cbb cbc cbk cbn cbo cbt cbu ccb ccc cck ccn cco cct ccu ckb ckc cko ckt cn- cnb cnc cnn cno cnt cnu co- cob coc cok con coo cot cou ctb ctc ctk ctn cto ctt ctu cub cuc cuk cun cuo cut cuu k-t kbb kbc kbk kbn kbo kbu kcb kcc kck kcn kct kcu kkb kkc kkk kkn kkt kku kn- knc knk knn kno knt knu kob koc kok kon koo kot kou ktb ktc ktk ktn kto ktt ktu kub kuc kuk kun kut kuu nbb nbc nbk nbn nbo nbt nbu ncb ncc nck ncn nco nct ncu nkc nkk nkn nko nkt nku nnb nnc nnk nnn nno nnt nnu no- nob noc nok non noo not nou ntb ntc ntk ntn nto ntt ntu nub nuc nuk nun nuo nut nuu ob- obb obc obk obn obo obt obu oc- ocb occ ock ocn oco oct ocu okb okc okk oko oku on- onb onc onk onn ono ont onu oo- oob ooc ook oon ooo oot ot- otb otc otk otn oto ott otu ou- ouc ouk oun ouo out tbb tbc tbk tbn tbo tbt tbu tcb tcc tck tcn tco tct tcu tkb tkc tkk tko tkt tnb tnc tnk tnn tno tnt to- tob toc tok ton too tot tou ttb ttc ttk ttn tto ttt ttu tub tuc tuk tun tuo tut tuu ubb ubc ubk ubn ubo ubt ubu ucb ucc uck ucn uco uct ucu ukb ukc ukk ukn uku un- unb unc unk unn uno unt unu uob uoc uok uon uoo uot utb utc utk utn uto utt utu uuc uun uut uuu