-er eee eeo eer ees eet eex eo- eoe eoo eor eos eot ere ero err ers ert es- ese eso esr ess est esx ete eto etr ets ett etx ex- exe exo exr exs ext exx oee oeo oer oes oet oex oo- ooo oor oos oot oox or- ore oro orr ors ort orx os- ose oso osr oss ost osx ot- ote oto otr ots ott ox- oxo oxt oxx re- ree reo rer res ret rex roe roo ror ros rot rox rrr rrs rrt rse rso rsr rss rst rsx rte rto rtr rts rtt rtx rxr rxs se- see seo ser ses set sex soe soo sor sos sot sox sr- sre sro srr srs srt srx ss- sse sso ssr sss sst ssx ste sto str sts stt stx sxs sxt t-x te- tee teo ter tes tet tex to- toe too tor tos tot tox tre tro trr trs trt trx tse tso tsr tss tst tsx tte tto ttr tts ttt ttx txe txs txt xee xer xes xet xex xoo xor xos xot xox xrt xrx xss xst xtr xts xtx xxo xxx