-er ddd dde ddp ddr dds ddx de- ded dee dep der des dev dex dpd dpe dpp dpr dps dpv drd dre drp drr drs drv drx dsd dse dsp dsr dss dsv dsx dvd dve dvp dvr dvs dvx dxd dxp dxr dxs dxx ed- edd ede edp edr eds edx eed eee eep eer ees eev eex ep- epd epe epp epr eps epx erd ere erp err ers erv es- esd ese esp esr ess esv esx evd eve evp evr evs evv ex- exd exe exp exr exs exx p-p pdd pde pdp pdr pds pdv pdx ped pee pep per pes pev pex ppd ppe ppp ppr pps ppv ppx prd pre prp prr prs prv prx ps- psd pse psp psr pss psv psx pvd pve pvp pvr pvs pvv pxe pxr pxs rdd rde rdp rdr rds rdv rdx re- red ree rep rer res rev rex rpd rpe rpp rpr rps rpv rpx rrd rrp rrr rrs rsd rse rsp rsr rss rsv rsx rvd rve rvp rvr rvs rvv rxp rxr rxs sdd sde sdp sdr sds sdv se- sed see sep ser ses sev sex spd spe spp spr sps spv spx sr- srd sre srp srr srs srv srx ss- ssd sse ssp ssr sss ssv ssx svd sve svp svr svs svv svx sxs v-e vdd vde vdp vdr vds vdv vdx ved vee vep ver ves vex vpd vpe vpp vpr vps vpx vrd vre vrp vrr vrs vsd vse vsp vsr vss vsv vvr vvs vvv vxd vxr vxs vxv xde xdr xds xdv xed xee xep xer xes xev xex xpd xpe xpp xps xrd xrx xsp xss xxp xxv xxx