bbb bbc bbk bbo bbr bby bcb bcc bck bco bcr bcy bcz bkb bkc bkk bko bkr bob boc bok boo bor boy boz brb brk bro brr bry brz by- byc byk byo byr byz bzo bzr bzz c-- cbb cbc cbk cbo cbr cby cbz ccb ccc cck cco ccr ccz ckb ckc cko cky co- cob coc cok coo cor coy coz crb crc crk cro crr cry crz cyb cyc cyk cyo cyr cz- czc czk czo k-z kbb kbc kbk kbo kbr kbz kcb kcc kck kcr kkb kkc kkk kkr kky kob koc kok koo kor koy koz krc krk kro krr kry kyc kyo kyr kyz kzo kzy ob- obb obc obk obo obr oby oc- ocb occ ock oco ocr ocz okb okc okk oko okr oo- oob ooc ook ooo oor or- orb orc ork oro orr ory orz oyo ozo ozz rbb rbc rbk rbo rbr rcb rcc rco rcr rkb rkc rkk rko rky rkz rob roc rok roo ror roy roz rrb rrc rrk rrr ry- ryc ryk ryo ryr ryy ryz rzb rzo rzy ybc ybr yby ybz ycc yco ycy ykk yob yoc yok yoo yor yoy yrc yro yyb yyc yyy yyz yzb yzr yzy zbb zbc zbr zby zco zo- zob zoc zok zoo zor zro zzr zzy zzz