b-u bbb bbc bbk bbo bbr bbu bby bcb bcc bck bco bcr bcu bcy bkb bkc bkk bko bkr bob boc bok boo bor bou boy brb brk bro brr bru bry bub buc buk buo bur buu buy by- byc byk byo byr byu c-- cbb cbc cbk cbo cbr cbu cby ccb ccc cck cco ccr ccu ckb ckc cko cky co- cob coc cok coo cor cou coy crb crc crk cro crr cru cry cub cuc cuk cuo cur cuu cuy cyb cyc cyk cyo cyr kbb kbc kbk kbo kbr kbu kcb kcc kck kcr kcu kkb kkc kkk kkr kku kky kob koc kok koo kor kou koy krc krk kro krr kru kry kub kuc kuk kur kuu kuy kyc kyo kyr kyu ob- obb obc obk obo obr obu oby oc- ocb occ ock oco ocr ocu okb okc okk oko okr oku oo- oob ooc ook ooo oor or- orb orc ork oro orr oru ory ou- ouc ouk ouo our oyo rbb rbc rbk rbo rbr rbu rcb rcc rco rcr rcu rkb rkc rkk rko rku rky rob roc rok roo ror rou roy rrb rrc rrk rrr rru rub ruc ruk ruo rur ruu ruy ry- ryc ryk ryo ryr ryu ryy ubb ubc ubk ubo ubr ubu uby ucb ucc uck uco ucr ucu ukb ukc ukk ukr uku uob uoc uok uoo uor ur- urb urc urk uro urr uru ury uuc uur uuu uyc uyo uyu ybc ybr yby ycc yco ycu ycy ykk yob yoc yok yoo yor you yoy yrc yro yru yuk yuo yur yuu yuy yyb yyc yyu yyy