-er ddd dde ddn ddp ddr ddx de- ded dee den dep der dex dnd dne dnn dnp dnr dpd dpe dpn dpp dpr drd dre drn drp drr drx dxd dxn dxp dxr dxx ed- edd ede edn edp edr edx eed eee een eep eer eex en- end ene enn enp enr ep- epd epe epn epp epr epx erd ere ern erp err ex- exd exe exp exr exx ndd nde ndn ndp ndr ne- ned nee nen nep ner nex nne nnn nnp npd npe npn npp npr nrd nre nrn nrp nrr nrx nxd p-p pdd pde pdn pdp pdr pdx ped pee pen pep per pex pn- pnd pne pnn pnp pnr pnx ppd ppe ppn ppp ppr ppx prd pre prn prp prr prx pxe pxr rdd rde rdn rdp rdr rdx re- red ree ren rep rer rex rnd rnn rnp rnr rpd rpe rpn rpp rpr rpx rrd rrn rrp rrr rxp rxr xde xdr xed xee xen xep xer xex xpd xpe xpn xpp xrd xrx xxp xxx