-er ddd dde ddf ddl ddr ddx de- ded dee def del der dex dfd dfe dff dfl dfr dfx dl- dld dle dlf dll dlr dlx drd dre drl drr drx dxd dxl dxr dxx ed- edd ede edf edl edr edx eed eee eef eel eer eex ef- efd efe eff efl efr efx eld ele elf ell elr elx erd ere erf erl err ex- exd exe exl exr exx fdd fde fdf fdl fdr fdx fed fee fef fel fer fex ffd ffe fff ffl ffr ffx fld fle flf fll flr flx frd fre frf frl frr fxe fxr fxx ldd lde ldf ldl ldr led lee lef lel ler lex lfd lfe lff lfl lfr lfx lld lle llf lll llr lrd lrf lrr lxd lxr lxx rdd rde rdf rdl rdr rdx re- red ree ref rel rer rex rfd rfe rff rfl rfr rld rle rlf rll rlr rrd rrf rrl rrr rxr xde xdf xdr xed xee xel xer xex xfe xfl xfx xld xlf xlr xrd xrf xrx xxl xxx