-er ddd dde ddo ddr dds ddt de- ded dee deo der des det dod doe doo dor dos dot drd dre dro drr drs drt dsd dse dso dsr dss dst dtd dte dto dtr dts dtt ed- edd ede edo edr eds edt eed eee eeo eer ees eet eo- eod eoe eoo eor eos eot erd ere ero err ers ert es- esd ese eso esr ess est etd ete eto etr ets ett odd ode odo odr ods odt oed oee oeo oer oes oet oo- ood ooo oor oos oot or- ord ore oro orr ors ort os- osd ose oso osr oss ost ot- otd ote oto otr ots ott rdd rde rdo rdr rds rdt re- red ree reo rer res ret rod roe roo ror ros rot rrd rrr rrs rrt rsd rse rso rsr rss rst rtd rte rto rtr rts rtt sdd sde sdo sdr sds sdt se- sed see seo ser ses set sod soe soo sor sos sot sr- srd sre sro srr srs srt ss- ssd sse sso ssr sss sst std ste sto str sts stt tdd tde tdo tdr tds tdt te- ted tee teo ter tes tet to- tod toe too tor tos tot trd tre tro trr trs trt tsd tse tso tsr tss tst ttd tte tto ttr tts ttt