-er ddd dde ddf ddi ddo ddr ddx de- ded dee def dei deo der dex dfd dfe dff dfi dfo dfr dfx di- did die dif dii dio dir dix dod doe dof doi doo dor dox drd dre dri dro drr drx dxd dxi dxo dxr dxx ed- edd ede edf edi edo edr edx eed eee eef eeo eer eex ef- efd efe eff efi efo efr efx eid eie eif eii eio eir eix eo- eod eoe eof eoi eoo eor erd ere erf eri ero err ex- exd exe exi exo exr exx fdd fde fdf fdi fdo fdr fdx fed fee fef fei feo fer fex ffd ffe fff ffi ffo ffr ffx fid fie fif fii fir fix foe fof foi foo for fox frd fre frf fri fro frr fxe fxi fxr fxx i-d i-f idd ide idf idi ido idr idx ie- ied iee ief iei ier iex ifd ife iff ifi ifo ifr ifx iid iie iif iii iio iir iix io- iod ioe iof ioi ioo ior ir- ird ire irf iri iro irr irx ixe ixi o-i odd ode odf odi odo odr oed oee oef oei oeo oer oex of- ofd ofe off ofi ofo ofr ofx oid oie oif oii oio oir oo- ood oof ooi ooo oor oox or- ord ore orf ori oro orr orx ox- oxf oxi oxo oxx rdd rde rdf rdi rdo rdr rdx re- red ree ref rei reo rer rex rfd rfe rff rfi rfo rfr rid rie rif rii rio rir rix rod roe rof roi roo ror rox rrd rrf rri rrr rxr xde xdf xdi xdr xed xee xer xex xfe xfx xie xii xio xix xod xof xoi xoo xor xox xrd xrf xrx xxi xxo xxx