bbb bbc bbh bbo bbs bcb bcc bch bco bcs bhb bhc bhh bho bhs bob boc boh boo bos bsb bsc bsh bso bss c-- cbb cbc cbh cbo cbs ccb ccc cch cco ccs ch- chb chc chh cho chs co- cob coc coh coo cos csb csc csh cso css hbb hbc hbh hbo hbs hcb hcc hch hco hcs hhb hhc hhh hho hhs hob hoc hoh hoo hos hsb hsc hsh hss ob- obb obc obh obo obs oc- ocb occ och oco ocs ohc ohh oho ohs oo- oob ooc ooh ooo oos os- osb osc osh oso oss sbb sbc sbh sbo sbs scb scc sch sco scs sh- shb shc shh sho shs sob soc soh soo sos ss- ssb ssc ssh sso sss