b-u bbb bbc bbd bbk bbn bbo bbu bcb bcc bcd bck bcn bco bcu bdb bdc bdd bdk bdo bdu bkb bkc bkk bkn bko bnb bnc bnd bnk bnn bno bnu bob boc bod bok bon boo bou bub buc bud buk bun buo buu c-- cbb cbc cbd cbk cbn cbo cbu ccb ccc ccd cck ccn cco ccu cdb cdc cdd cdk cdn cdo cdu ckb ckc ckd cko cn- cnb cnc cnd cnn cno cnu co- cob coc cod cok con coo cou cub cuc cud cuk cun cuo cuu dbb dbc dbd dbk dbn dbo dbu dcb dcc dcd dck dcn dco dcu ddb ddc ddd ddk ddn ddo ddu dkb dkc dkk dko dku dnb dnc dnd dnk dnn dno dob doc dod dok don doo dou dub duc dud duk dun duo kbb kbc kbd kbk kbn kbo kbu kcb kcc kcd kck kcn kcu kdb kdc kdk kdo kdu kkb kkc kkk kkn kku kn- knc knd knk knn kno knu kob koc kod kok kon koo kou kub kuc kud kuk kun kuu nbb nbc nbd nbk nbn nbo nbu ncb ncc ncd nck ncn nco ncu ndb ndc ndd ndk ndn ndo ndu nkc nkk nkn nko nku nnb nnc nnk nnn nno nnu no- nob noc nod nok non noo nou nub nuc nud nuk nun nuo nuu ob- obb obc obd obk obn obo obu oc- ocb occ ocd ock ocn oco ocu odb odc odd odn odo odu okb okc okd okk oko oku on- onb onc ond onk onn ono onu oo- oob ooc ood ook oon ooo ou- ouc oud ouk oun ouo ubb ubc ubk ubn ubo ubu ucb ucc ucd uck ucn uco ucu udb udc udd udk udn udo udu ukb ukc ukk ukn uku un- unb unc und unk unn uno unu uob uoc uod uok uon uoo uuc uun uuu