c-- ccc cch cck cco ccs ch- chc chh chk cho chs ckc ckh cko cks co- coc coh cok coo cos csc csh csk cso css hcc hch hck hco hcs hhc hhh hhk hho hhs hkh hkk hko hks hoc hoh hok hoo hos hsc hsh hsk hss kcc kch kck kcs khh khk kho khs kkc kkh kkk kks koc koh kok koo kos ksc ksh ksk kso kss oc- occ och ock oco ocs ohc ohh oho ohs okc okk oko oks oo- ooc ooh ook ooo oos os- osc osh osk oso oss scc sch sck sco scs sh- shc shh shk sho shs sk- skc skh skk sko sks soc soh sok soo sos ss- ssc ssh ssk sso sss