-er ddd dde ddm ddo ddr ddx de- ded dee dem deo der dex dmd dme dmm dmo dmr dmx dod doe dom doo dor dox drd dre drm dro drr drx dxd dxo dxr dxx ed- edd ede edm edo edr edx eed eee eem eeo eer eex em- emd eme emm emo emr emx eo- eod eoe eom eoo eor erd ere erm ero err ex- exd exe exo exr exx m-o m-r mdd mde mdm mdo mdr mdx med mee mem meo mer mex mmd mme mmm mmo mmr mmx mod moe mom moo mor mox mrd mre mrm mro mrr mrx mxd mxr odd ode odm odo odr oed oee oem oeo oer oex om- omd ome omm omo omr omx oo- ood oom ooo oor oox or- ord ore orm oro orr orx ox- oxo oxx rdd rde rdm rdo rdr rdx re- red ree rem reo rer rex rmd rme rmm rmo rmr rmx rod roe rom roo ror rox rrd rrm rrr rxr xde xdm xdr xed xee xem xer xex xmd xmm xmo xmr xmx xod xom xoo xor xox xrd xrx xxo xxx