-er ddd dde ddo ddp ddr dds ddt de- ded dee deo dep der des det dod doe doo dop dor dos dot dpd dpe dpo dpp dpr dps dpt drd dre dro drp drr drs drt dsd dse dso dsp dsr dss dst dtd dte dto dtp dtr dts dtt ed- edd ede edo edp edr eds edt eed eee eeo eep eer ees eet eo- eod eoe eoo eop eor eos eot ep- epd epe epo epp epr eps ept erd ere ero erp err ers ert es- esd ese eso esp esr ess est etd ete eto etp etr ets ett odd ode odo odp odr ods odt oed oee oeo oep oer oes oet oo- ood ooo oop oor oos oot op- opd ope opo opp opr ops opt or- ord ore oro orp orr ors ort os- osd ose oso osp osr oss ost ot- otd ote oto otp otr ots ott p-p pdd pde pdo pdp pdr pds pdt ped pee peo pep per pes pet pod poe poo pop por pos pot ppd ppe ppo ppp ppr pps ppt prd pre pro prp prr prs prt ps- psd pse pso psp psr pss pst pt- ptd pte pto ptp ptr pts ptt rdd rde rdo rdp rdr rds rdt re- red ree reo rep rer res ret rod roe roo rop ror ros rot rpd rpe rpo rpp rpr rps rpt rrd rrp rrr rrs rrt rsd rse rso rsp rsr rss rst rtd rte rto rtp rtr rts rtt sdd sde sdo sdp sdr sds sdt se- sed see seo sep ser ses set sod soe soo sop sor sos sot spd spe spo spp spr sps spt sr- srd sre sro srp srr srs srt ss- ssd sse sso ssp ssr sss sst std ste sto stp str sts stt tdd tde tdo tdp tdr tds tdt te- ted tee teo tep ter tes tet to- tod toe too top tor tos tot tpd tpe tpo tpp tpr tps tpt trd tre tro trp trr trs trt tsd tse tso tsp tsr tss tst ttd tte tto ttp ttr tts ttt