-er eee eeo eep eer ees eet eex eo- eoe eoo eop eor eos eot ep- epe epo epp epr eps ept epx ere ero erp err ers ert es- ese eso esp esr ess est esx ete eto etp etr ets ett etx ex- exe exo exp exr exs ext exx oee oeo oep oer oes oet oex oo- ooo oop oor oos oot oox op- ope opo opp opr ops opt opx or- ore oro orp orr ors ort orx os- ose oso osp osr oss ost osx ot- ote oto otp otr ots ott ox- oxo oxt oxx p-p pee peo pep per pes pet pex poe poo pop por pos pot pox ppe ppo ppp ppr pps ppt ppx pre pro prp prr prs prt prx ps- pse pso psp psr pss pst psx pt- pte pto ptp ptr pts ptt ptx pxe pxr pxs pxt re- ree reo rep rer res ret rex roe roo rop ror ros rot rox rpe rpo rpp rpr rps rpt rpx rrp rrr rrs rrt rse rso rsp rsr rss rst rsx rte rto rtp rtr rts rtt rtx rxp rxr rxs se- see seo sep ser ses set sex soe soo sop sor sos sot sox spe spo spp spr sps spt spx sr- sre sro srp srr srs srt srx ss- sse sso ssp ssr sss sst ssx ste sto stp str sts stt stx sxs sxt t-x te- tee teo tep ter tes tet tex to- toe too top tor tos tot tox tpe tpo tpp tpr tps tpt tpx tre tro trp trr trs trt trx tse tso tsp tsr tss tst tsx tte tto ttp ttr tts ttt ttx txe txs txt xee xep xer xes xet xex xoo xop xor xos xot xox xpe xpo xpp xps xpt xrt xrx xsp xss xst xtp xtr xts xtx xxo xxp xxx