c-- ccc cck cco ccs ccv ckc cko cks cky co- coc cok coo cos cov coy csc csk cso css csv csy cvc cvk cvo cvs cvv cyc cyk cyo cys kcc kck kcs kkc kkk kks kkv kky koc kok koo kos koy ksc ksk kso kss ksv kvk kvo kvs kvv kyc kyo kys oc- occ ock oco ocs ocv okc okk oko oks oo- ooc ook ooo oos oov os- osc osk oso oss osv ov- ovc ovo ovs ovv oyo oys scc sck sco scs scv sk- skc skk sko sks sky soc sok soo sos sov soy ss- ssc ssk sso sss ssv svc svk svo svs svv svy sy- syc syk sys vcc vco vcs vcy voc vok voo vos vov voy vsc vsk vso vss vsv vvc vvo vvs vvv ycc yco ycs ycv ycy ykk yoc yok yoo yos yoy ysc ysk yso yss ysy yvo yvy yyc yys yyy