bbb bbc bbh bbo bbr bbs bcb bcc bch bco bcr bcs bhb bhc bhh bho bhr bhs bob boc boh boo bor bos brb brh bro brr brs bsb bsc bsh bso bsr bss c-- cbb cbc cbh cbo cbr cbs ccb ccc cch cco ccr ccs ch- chb chc chh cho chr chs co- cob coc coh coo cor cos crb crc crh cro crr crs csb csc csh cso csr css hbb hbc hbh hbo hbr hbs hcb hcc hch hco hcr hcs hhb hhc hhh hho hhr hhs hob hoc hoh hoo hor hos hr- hrb hrc hrh hro hrr hrs hsb hsc hsh hsr hss ob- obb obc obh obo obr obs oc- ocb occ och oco ocr ocs ohc ohh oho ohr ohs oo- oob ooc ooh ooo oor oos or- orb orc orh oro orr ors os- osb osc osh oso osr oss rbb rbc rbh rbo rbr rbs rcb rcc rch rco rcr rcs rh- rhb rhc rhh rho rhr rhs rob roc roh roo ror ros rrb rrc rrh rrr rrs rsb rsc rsh rso rsr rss sbb sbc sbh sbo sbr sbs scb scc sch sco scr scs sh- shb shc shh sho shr shs sob soc soh soo sor sos sr- srb src srh sro srr srs ss- ssb ssc ssh sso ssr sss