-er c-- ccc ccd cce ccf cck cco ccr ccs cdc cdd cde cdf cdk cdo cdr cds ce- cec ced cee cef cek ceo cer ces cfc cfd cfe cff cfk cfo cfr cfs ckc ckd cko cks co- coc cod coe cof cok coo cor cos crc crd cre crf crk cro crr crs csc csd cse csf csk cso csr css dcc dcd dce dcf dck dco dcr dcs ddc ddd dde ddf ddk ddo ddr dds de- dec ded dee def dek deo der des dfc dfd dfe dff dfk dfo dfr dfs dkc dke dkk dko dkr dks doc dod doe dof dok doo dor dos drc drd dre drk dro drr drs dsc dsd dse dsf dsk dso dsr dss ec- ecc ecd ece ecf eck eco ecr ecs ed- edc edd ede edf edk edo edr eds eec eed eee eef eek eeo eer ees ef- efc efd efe eff efo efr efs ekc ekd eke ekf eko ekr eks eo- eoc eod eoe eof eok eoo eor eos erc erd ere erf erk ero err ers es- esc esd ese esf esk eso esr ess fcc fcd fce fcf fck fco fcr fcs fdc fdd fde fdf fdk fdo fdr fds fec fed fee fef fek feo fer fes ffc ffd ffe fff ffk ffo ffr ffs fkc fkf fkk foc foe fof fok foo for fos frc frd fre frf frk fro frr frs fsc fsd fse fsf fsk fso fsr fss kcc kcd kce kck kcr kcs kdc kde kdf kdk kdo kdr kds ke- kec ked kee kef kek keo ker kes kfc kfd kff kfo kfs kkc kke kkk kkr kks koc kod koe kof kok koo kor kos krc krd krf krk kro krr krs ksc ksd kse ksf ksk kso ksr kss oc- occ ocd ocf ock oco ocr ocs odc odd ode odf odo odr ods oec oed oee oef oeo oer oes of- ofc ofd ofe off ofo ofr ofs okc okd oke okk oko okr oks oo- ooc ood oof ook ooo oor oos or- orc ord ore orf ork oro orr ors os- osc osd ose osf osk oso osr oss rcc rcd rce rcf rco rcr rcs rdc rdd rde rdf rdo rdr rds re- rec red ree ref rek reo rer res rfc rfd rfe rff rfk rfo rfr rfs rkc rke rkf rkk rko rks roc rod roe rof rok roo ror ros rrc rrd rrf rrk rrr rrs rsc rsd rse rsf rsk rso rsr rss scc scd sce scf sck sco scr scs sdc sdd sde sdf sdk sdo sdr sds se- sec sed see sef sek seo ser ses sfc sfd sfe sff sfk sfo sfr sfs sk- skc skd ske skf skk sko skr sks soc sod soe sof sok soo sor sos sr- src srd sre srf srk sro srr srs ss- ssc ssd sse ssf ssk sso ssr sss