-er ddd dde ddf ddk ddo ddr ddt de- ded dee def dek deo der det dfd dfe dff dfk dfo dfr dft dke dkk dko dkr dkt dod doe dof dok doo dor dot drd dre drk dro drr drt dtd dte dtf dtk dto dtr dtt ed- edd ede edf edk edo edr edt eed eee eef eek eeo eer eet ef- efd efe eff efo efr eft ekd eke ekf eko ekr ekt eo- eod eoe eof eok eoo eor eot erd ere erf erk ero err ert etd ete etf etk eto etr ett fdd fde fdf fdk fdo fdr fdt fed fee fef fek feo fer fet ffd ffe fff ffk ffo ffr fft fkf fkk fkt foe fof fok foo for fot frd fre frf frk fro frr frt ftd fte ftf ftk fto ftr ftt k-t kde kdf kdk kdo kdr kdt ke- ked kee kef kek keo ker ket kfd kff kfo kke kkk kkr kkt kod koe kof kok koo kor kot krd krf krk kro krr krt kte ktf ktk kto ktr ktt odd ode odf odo odr odt oed oee oef oeo oer oet of- ofd ofe off ofo ofr oft okd oke okk oko okr oo- ood oof ook ooo oor oot or- ord ore orf ork oro orr ort ot- otd ote otf otk oto otr ott rdd rde rdf rdo rdr rdt re- red ree ref rek reo rer ret rfd rfe rff rfk rfo rfr rft rke rkf rkk rko rkt rod roe rof rok roo ror rot rrd rrf rrk rrr rrt rtd rte rtf rtk rto rtr rtt tdd tde tdf tdk tdo tdr tdt te- ted tee tef tek teo ter tet tfd tfe tff tfk tfo tfr tft tke tkk tko tkr tkt to- tod toe tof tok too tor tot trd tre trf trk tro trr trt ttd tte ttf ttk tto ttr ttt