bbb bbc bbh bbk bbo bbr bcb bcc bch bck bco bcr bhb bhc bhh bhk bho bhr bkb bkc bkk bko bkr bob boc boh bok boo bor brb brh brk bro brr c-- cbb cbc cbh cbk cbo cbr ccb ccc cch cck cco ccr ch- chb chc chh chk cho chr ckb ckc ckh cko co- cob coc coh cok coo cor crb crc crh crk cro crr hbb hbc hbh hbk hbo hbr hcb hcc hch hck hco hcr hhb hhc hhh hhk hho hhr hkb hkh hkk hko hkr hob hoc hoh hok hoo hor hr- hrb hrc hrh hrk hro hrr kbb kbc kbh kbk kbo kbr kcb kcc kch kck kcr khh khk kho khr kkb kkc kkh kkk kkr kob koc koh kok koo kor krc krk kro krr ob- obb obc obh obk obo obr oc- ocb occ och ock oco ocr ohc ohh oho ohr okb okc okk oko okr oo- oob ooc ooh ook ooo oor or- orb orc orh ork oro orr rbb rbc rbh rbk rbo rbr rcb rcc rch rco rcr rh- rhb rhc rhh rho rhr rkb rkc rkk rko rob roc roh rok roo ror rrb rrc rrh rrk rrr