c-- ccc ccf cck cco ccp ccr ccs cfc cff cfk cfo cfp cfr cfs ckc cko cks co- coc cof cok coo cop cor cos cpc cpf cpk cpo cpp cpr cps crc crf crk cro crp crr crs csc csf csk cso csp csr css fcc fcf fck fco fcp fcr fcs ffc fff ffk ffo ffp ffr ffs fkc fkf fkk fkp foc fof fok foo fop for fos fpc fpk fpo fpp fpr fps frc frf frk fro frp frr frs fsc fsf fsk fso fsp fsr fss kcc kck kcp kcr kcs kfc kff kfo kfs kkc kkk kkp kkr kks koc kof kok koo kop kor kos kpc kpf kpk kpo kpp kpr kps krc krf krk kro krp krr krs ksc ksf ksk kso ksp ksr kss oc- occ ocf ock oco ocp ocr ocs of- ofc off ofo ofp ofr ofs okc okk oko okp okr oks oo- ooc oof ook ooo oop oor oos op- opc opf opk opo opp opr ops or- orc orf ork oro orp orr ors os- osc osf osk oso osp osr oss p-p pcc pcf pck pco pcp pcr pcs pfc pff pfk pfo pfp pfr pfs pkc pkf pko pkp pkr pks poc pof pok poo pop por pos ppc ppf ppk ppo ppp ppr pps prc prf prk pro prp prr prs ps- psc psf psk pso psp psr pss rcc rcf rco rcp rcr rcs rfc rff rfk rfo rfp rfr rfs rkc rkf rkk rko rkp rks roc rof rok roo rop ror ros rpc rpf rpk rpo rpp rpr rps rrc rrf rrk rrp rrr rrs rsc rsf rsk rso rsp rsr rss scc scf sck sco scp scr scs sfc sff sfk sfo sfp sfr sfs sk- skc skf skk sko skp skr sks soc sof sok soo sop sor sos spc spf spk spo spp spr sps sr- src srf srk sro srp srr srs ss- ssc ssf ssk sso ssp ssr sss