b-u bbb bbc bbk bbn bbo bbu bcb bcc bck bcn bco bcu bkb bkc bkk bkn bko bnb bnc bnk bnn bno bnu bob boc bok bon boo bou bub buc buk bun buo buu c-- cbb cbc cbk cbn cbo cbu ccb ccc cck ccn cco ccu ckb ckc cko cn- cnb cnc cnn cno cnu co- cob coc cok con coo cou cub cuc cuk cun cuo cuu kbb kbc kbk kbn kbo kbu kcb kcc kck kcn kcu kkb kkc kkk kkn kku kn- knc knk knn kno knu kob koc kok kon koo kou kub kuc kuk kun kuu nbb nbc nbk nbn nbo nbu ncb ncc nck ncn nco ncu nkc nkk nkn nko nku nnb nnc nnk nnn nno nnu no- nob noc nok non noo nou nub nuc nuk nun nuo nuu ob- obb obc obk obn obo obu oc- ocb occ ock ocn oco ocu okb okc okk oko oku on- onb onc onk onn ono onu oo- oob ooc ook oon ooo ou- ouc ouk oun ouo ubb ubc ubk ubn ubo ubu ucb ucc uck ucn uco ucu ukb ukc ukk ukn uku un- unb unc unk unn uno unu uob uoc uok uon uoo uuc uun uuu