-er ddd dde ddp ddr dds ddt de- ded dee dep der des det dpd dpe dpp dpr dps dpt drd dre drp drr drs drt dsd dse dsp dsr dss dst dtd dte dtp dtr dts dtt ed- edd ede edp edr eds edt eed eee eep eer ees eet ep- epd epe epp epr eps ept erd ere erp err ers ert es- esd ese esp esr ess est etd ete etp etr ets ett p-p pdd pde pdp pdr pds pdt ped pee pep per pes pet ppd ppe ppp ppr pps ppt prd pre prp prr prs prt ps- psd pse psp psr pss pst pt- ptd pte ptp ptr pts ptt rdd rde rdp rdr rds rdt re- red ree rep rer res ret rpd rpe rpp rpr rps rpt rrd rrp rrr rrs rrt rsd rse rsp rsr rss rst rtd rte rtp rtr rts rtt sdd sde sdp sdr sds sdt se- sed see sep ser ses set spd spe spp spr sps spt sr- srd sre srp srr srs srt ss- ssd sse ssp ssr sss sst std ste stp str sts stt tdd tde tdp tdr tds tdt te- ted tee tep ter tes tet tpd tpe tpp tpr tps tpt trd tre trp trr trs trt tsd tse tsp tsr tss tst ttd tte ttp ttr tts ttt