-er -ol eee eef eel eeo eer eet eex ef- efe eff efl efo efr eft efx ele elf ell elo elr elt elx eo- eoe eof eol eoo eor eot ere erf erl ero err ert ete etf etl eto etr ett etx ex- exe exl exo exr ext exx fee fef fel feo fer fet fex ffe fff ffl ffo ffr fft ffx fle flf fll flo flr flt flx foe fof fol foo for fot fox fre frf frl fro frr frt fte ftf ftl fto ftr ftt ftx fxe fxr fxt fxx lee lef lel leo ler let lex lfe lff lfl lfo lfr lft lfx lle llf lll llo llr llt loe lof lol loo lor lot lox lrf lro lrr lrt lte ltf ltl lto ltr ltt ltx lxo lxr lxx oee oef oel oeo oer oet oex of- ofe off ofl ofo ofr oft ofx ole olf oll olo olt oo- oof ool ooo oor oot oox or- ore orf orl oro orr ort orx ot- ote otf otl oto otr ott ox- oxf oxo oxt oxx re- ree ref rel reo rer ret rex rfe rff rfl rfo rfr rft rle rlf rll rlo rlr rlt roe rof rol roo ror rot rox rrf rrl rrr rrt rte rtf rtl rto rtr rtt rtx rxr t-x te- tee tef tel teo ter tet tex tfe tff tfl tfo tfr tft tfx tle tlf tll tlo tlr tlt tlx to- toe tof tol too tor tot tox tre trf trl tro trr trt trx tte ttf ttl tto ttr ttt ttx txe txf txl txt xee xel xer xet xex xfe xfl xft xfx xlf xlr xlt xof xoo xor xot xox xrf xrt xrx xtf xtr xtx xxl xxo xxx