c-- ccc ccf cck cco ccr ccs cfc cff cfk cfo cfr cfs ckc cko cks cky co- coc cof cok coo cor cos coy crc crf crk cro crr crs cry csc csf csk cso csr css csy cyc cyf cyk cyo cyr cys fcc fcf fck fco fcr fcs fcy ffc fff ffk ffo ffr ffs ffy fkc fkf fkk foc fof fok foo for fos foy frc frf frk fro frr frs fry fsc fsf fsk fso fsr fss fy- fyc fyk fyo kcc kck kcr kcs kfc kff kfo kfs kkc kkk kkr kks kky koc kof kok koo kor kos koy krc krf krk kro krr krs kry ksc ksf ksk kso ksr kss kyc kyo kyr kys oc- occ ocf ock oco ocr ocs of- ofc off ofo ofr ofs okc okk oko okr oks oo- ooc oof ook ooo oor oos or- orc orf ork oro orr ors ory os- osc osf osk oso osr oss oyo oys rcc rcf rco rcr rcs rfc rff rfk rfo rfr rfs rkc rkf rkk rko rks rky roc rof rok roo ror ros roy rrc rrf rrk rrr rrs rsc rsf rsk rso rsr rss ry- ryc ryf ryk ryo ryr rys ryy scc scf sck sco scr scs sfc sff sfk sfo sfr sfs sk- skc skf skk sko skr sks sky soc sof sok soo sor sos soy sr- src srf srk sro srr srs sry ss- ssc ssf ssk sso ssr sss sy- syc syk syr sys ycc ycf yco ycs ycy yfc yff yfr yfs ykk yoc yof yok yoo yor yos yoy yrc yrf yro yrs ysc ysk yso ysr yss ysy yyc yyf yys yyy