-er ddd dde ddo ddp ddr dds de- ded dee deo dep der des dod doe doo dop dor dos dpd dpe dpo dpp dpr dps drd dre dro drp drr drs dsd dse dso dsp dsr dss ed- edd ede edo edp edr eds eed eee eeo eep eer ees eo- eod eoe eoo eop eor eos ep- epd epe epo epp epr eps erd ere ero erp err ers es- esd ese eso esp esr ess odd ode odo odp odr ods oed oee oeo oep oer oes oo- ood ooo oop oor oos op- opd ope opo opp opr ops or- ord ore oro orp orr ors os- osd ose oso osp osr oss p-p pdd pde pdo pdp pdr pds ped pee peo pep per pes pod poe poo pop por pos ppd ppe ppo ppp ppr pps prd pre pro prp prr prs ps- psd pse pso psp psr pss rdd rde rdo rdp rdr rds re- red ree reo rep rer res rod roe roo rop ror ros rpd rpe rpo rpp rpr rps rrd rrp rrr rrs rsd rse rso rsp rsr rss sdd sde sdo sdp sdr sds se- sed see seo sep ser ses sod soe soo sop sor sos spd spe spo spp spr sps sr- srd sre sro srp srr srs ss- ssd sse sso ssp ssr sss