c-- ccc ccd ccf cck cco ccr ccs cdc cdd cdf cdk cdo cdr cds cfc cfd cff cfk cfo cfr cfs ckc ckd cko cks co- coc cod cof cok coo cor cos crc crd crf crk cro crr crs csc csd csf csk cso csr css dcc dcd dcf dck dco dcr dcs ddc ddd ddf ddk ddo ddr dds dfc dfd dff dfk dfo dfr dfs dkc dkk dko dkr dks doc dod dof dok doo dor dos drc drd drk dro drr drs dsc dsd dsf dsk dso dsr dss fcc fcd fcf fck fco fcr fcs fdc fdd fdf fdk fdo fdr fds ffc ffd fff ffk ffo ffr ffs fkc fkf fkk foc fof fok foo for fos frc frd frf frk fro frr frs fsc fsd fsf fsk fso fsr fss kcc kcd kck kcr kcs kdc kdf kdk kdo kdr kds kfc kfd kff kfo kfs kkc kkk kkr kks koc kod kof kok koo kor kos krc krd krf krk kro krr krs ksc ksd ksf ksk kso ksr kss oc- occ ocd ocf ock oco ocr ocs odc odd odf odo odr ods of- ofc ofd off ofo ofr ofs okc okd okk oko okr oks oo- ooc ood oof ook ooo oor oos or- orc ord orf ork oro orr ors os- osc osd osf osk oso osr oss rcc rcd rcf rco rcr rcs rdc rdd rdf rdo rdr rds rfc rfd rff rfk rfo rfr rfs rkc rkf rkk rko rks roc rod rof rok roo ror ros rrc rrd rrf rrk rrr rrs rsc rsd rsf rsk rso rsr rss scc scd scf sck sco scr scs sdc sdd sdf sdk sdo sdr sds sfc sfd sff sfk sfo sfr sfs sk- skc skd skf skk sko skr sks soc sod sof sok soo sor sos sr- src srd srf srk sro srr srs ss- ssc ssd ssf ssk sso ssr sss