-er ddd dde ddp ddr dds de- ded dee dep der des dpd dpe dpp dpr dps drd dre drp drr drs dsd dse dsp dsr dss ed- edd ede edp edr eds eed eee eep eer ees ep- epd epe epp epr eps erd ere erp err ers es- esd ese esp esr ess p-p pdd pde pdp pdr pds ped pee pep per pes ppd ppe ppp ppr pps prd pre prp prr prs ps- psd pse psp psr pss rdd rde rdp rdr rds re- red ree rep rer res rpd rpe rpp rpr rps rrd rrp rrr rrs rsd rse rsp rsr rss sdd sde sdp sdr sds se- sed see sep ser ses spd spe spp spr sps sr- srd sre srp srr srs ss- ssd sse ssp ssr sss