eee eef eeo eep ees eet ef- efe eff efo efp efs eft eo- eoe eof eoo eop eos eot ep- epe epf epo epp eps ept es- ese esf eso esp ess est ete etf eto etp ets ett fee fef feo fep fes fet ffe fff ffo ffp ffs fft foe fof foo fop fos fot fpe fpo fpp fps fpt fse fsf fso fsp fss fst fte ftf fto ftp fts ftt oee oef oeo oep oes oet of- ofe off ofo ofp ofs oft oo- oof ooo oop oos oot op- ope opf opo opp ops opt os- ose osf oso osp oss ost ot- ote otf oto otp ots ott p-p pee pef peo pep pes pet pfe pff pfo pfp pfs pft poe pof poo pop pos pot ppe ppf ppo ppp pps ppt ps- pse psf pso psp pss pst pt- pte ptf pto ptp pts ptt se- see sef seo sep ses set sfe sff sfo sfp sfs sft soe sof soo sop sos sot spe spf spo spp sps spt ss- sse ssf sso ssp sss sst ste stf sto stp sts stt te- tee tef teo tep tes tet tfe tff tfo tfp tfs tft to- toe tof too top tos tot tpe tpf tpo tpp tps tpt tse tsf tso tsp tss tst tte ttf tto ttp tts ttt