-er c-- ccc ccd cce ccf cco ccr ccs cdc cdd cde cdf cdo cdr cds ce- cec ced cee cef ceo cer ces cfc cfd cfe cff cfo cfr cfs co- coc cod coe cof coo cor cos crc crd cre crf cro crr crs csc csd cse csf cso csr css dcc dcd dce dcf dco dcr dcs ddc ddd dde ddf ddo ddr dds de- dec ded dee def deo der des dfc dfd dfe dff dfo dfr dfs doc dod doe dof doo dor dos drc drd dre dro drr drs dsc dsd dse dsf dso dsr dss ec- ecc ecd ece ecf eco ecr ecs ed- edc edd ede edf edo edr eds eec eed eee eef eeo eer ees ef- efc efd efe eff efo efr efs eo- eoc eod eoe eof eoo eor eos erc erd ere erf ero err ers es- esc esd ese esf eso esr ess fcc fcd fce fcf fco fcr fcs fdc fdd fde fdf fdo fdr fds fec fed fee fef feo fer fes ffc ffd ffe fff ffo ffr ffs foc foe fof foo for fos frc frd fre frf fro frr frs fsc fsd fse fsf fso fsr fss oc- occ ocd ocf 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 oo- ooc ood oof ooo oor oos or- orc ord ore orf oro orr ors os- osc osd ose osf oso osr oss rcc rcd rce rcf rco rcr rcs rdc rdd rde rdf rdo rdr rds re- rec red ree ref reo rer res rfc rfd rfe rff rfo rfr rfs roc rod roe rof roo ror ros rrc rrd rrf rrr rrs rsc rsd rse rsf rso rsr rss scc scd sce scf sco scr scs sdc sdd sde sdf sdo sdr sds se- sec sed see sef seo ser ses sfc sfd sfe sff sfo sfr sfs soc sod soe sof soo sor sos sr- src srd sre srf sro srr srs ss- ssc ssd sse ssf sso ssr sss