-er ddd dde ddi ddr ddx de- ded dee dei der dev dex di- did die dii dir div dix drd dre dri drr drv drx dvd dve dvi dvr dvx dxd dxi dxr dxx ed- edd ede edi edr edx eed eee eer eev eex eid eie eii eir eiv eix erd ere eri err erv evd eve evi evr evv ex- exd exe exi exr exx i-d i-v idd ide idi idr idv idx ie- ied iee iei ier iev iex iid iie iii iir iix ir- ird ire iri irr irv irx ivd ive ivi ivr ivv ivx ixe ixi rdd rde rdi rdr rdv rdx re- red ree rei rer rev rex rid rie rii rir riv rix rrd rri rrr rvd rve rvi rvr rvv rxr v-e vdd vde vdi vdr vdv vdx ved vee vei ver vex vi- vid vie vii vir viv vix vrd vre vri vrr vvi vvr vvv vxd vxr vxv xde xdi xdr xdv xed xee xer xev xex xie xii xiv xix xrd xrx xvi xxi xxv xxx