-er ddd dde ddf ddo ddr dds de- ded dee def deo der des dfd dfe dff dfo dfr dfs dod doe dof doo dor dos drd dre dro drr drs dsd dse dsf dso dsr dss ed- edd ede edf edo edr eds eed eee eef eeo eer ees ef- efd efe eff efo efr efs eo- eod eoe eof eoo eor eos erd ere erf ero err ers es- esd ese esf eso esr ess fdd fde fdf fdo fdr fds fed fee fef feo fer fes ffd ffe fff ffo ffr ffs foe fof foo for fos frd fre frf fro frr frs fsd fse fsf fso fsr fss odd ode odf odo odr ods oed oee oef oeo oer oes of- ofd ofe off ofo ofr ofs oo- ood oof ooo oor oos or- ord ore orf oro orr ors os- osd ose osf oso osr oss rdd rde rdf rdo rdr rds re- red ree ref reo rer res rfd rfe rff rfo rfr rfs rod roe rof roo ror ros rrd rrf rrr rrs rsd rse rsf rso rsr rss sdd sde sdf sdo sdr sds se- sed see sef seo ser ses sfd sfe sff sfo sfr sfs sod soe sof soo sor sos sr- srd sre srf sro srr srs ss- ssd sse ssf sso ssr sss