c-- ccc cck cco ccp ccr ccs ckc cko cks co- coc cok coo cop cor cos cpc cpk cpo cpp cpr cps crc crk cro crp crr crs csc csk cso csp csr css kcc kck kcp kcr kcs kkc kkk kkp kkr kks koc kok koo kop kor kos kpc kpk kpo kpp kpr kps krc krk kro krp krr krs ksc ksk kso ksp ksr kss oc- occ ock oco ocp ocr ocs okc okk oko okp okr oks oo- ooc ook ooo oop oor oos op- opc opk opo opp opr ops or- orc ork oro orp orr ors os- osc osk oso osp osr oss p-p pcc pck pco pcp pcr pcs pkc pko pkp pkr pks poc pok poo pop por pos ppc ppk ppo ppp ppr pps prc prk pro prp prr prs ps- psc psk pso psp psr pss rcc rco rcp rcr rcs rkc rkk rko rkp rks roc rok roo rop ror ros rpc rpk rpo rpp rpr rps rrc rrk rrp rrr rrs rsc rsk rso rsp rsr rss scc sck sco scp scr scs sk- skc skk sko skp skr sks soc sok soo sop sor sos spc spk spo spp spr sps sr- src srk sro srp srr srs ss- ssc ssk sso ssp ssr sss