-er ddd dde ddi ddp ddr dds ddt de- ded dee dei dep der des det di- did die dii dip dir dis dit dpd dpe dpi dpp dpr dps dpt drd dre dri drp drr drs drt dsd dse dsi dsp dsr dss dst dtd dte dti dtp dtr dts dtt ed- edd ede edi edp edr eds edt eed eee eep eer ees eet eid eie eii eip eir eis eit ep- epd epe epi epp epr eps ept erd ere eri erp err ers ert es- esd ese esi esp esr ess est etd ete eti etp etr ets ett i-d idd ide idi idp idr ids idt ie- ied iee iei iep ier ies iet iid iie iii iip iir iis iit ipd ipe ipi ipp ipr ips ipt ir- ird ire iri irp irr irs irt is- isd ise isi isp isr iss ist itd ite iti itp its itt p-p pdd pde pdi pdp pdr pds pdt ped pee pei pep per pes pet pid pie pii pip pir pis pit ppd ppe ppi ppp ppr pps ppt prd pre pri prp prr prs prt ps- psd pse psi psp psr pss pst pt- ptd pte pti ptp ptr pts ptt rdd rde rdi rdp rdr rds rdt re- red ree rei rep rer res ret rid rie rii rip rir ris rit rpd rpe rpi rpp rpr rps rpt rrd rri rrp rrr rrs rrt rsd rse rsi rsp rsr rss rst rtd rte rti rtp rtr rts rtt sdd sde sdi sdp sdr sds sdt se- sed see sei sep ser ses set sid sie sii sip sir sis sit spd spe spi spp spr sps spt sr- srd sre sri srp srr srs srt ss- ssd sse ssi ssp ssr sss sst std ste sti stp str sts stt tdd tde tdi tdp tdr tds tdt te- ted tee tei tep ter tes tet tid tie tii tip tir tis tit tpd tpe tpi tpp tpr tps tpt trd tre tri trp trr trs trt tsd tse tsi tsp tsr tss tst ttd tte tti ttp ttr tts ttt