-er eee eef eem eer ees eet ef- efe eff efm efr efs eft em- eme emf emm emr ems emt ere erf erm err ers ert es- ese esf esm esr ess est ete etf etm etr ets ett fee fef fem fer fes fet ffe fff ffm ffr ffs fft fme fmf fmm fmr fms fmt fre frf frm frr frs frt fse fsf fsm fsr fss fst fte ftf ftm ftr fts ftt m-f m-r mee mef mem mer mes met mfe mff mfm mfr mfs mft mme mmf mmm mmr mms mmt mre mrf mrm mrr mrs mrt mse msf msm msr mss mst mte mtf mtm mtr mts mtt re- ree ref rem rer res ret rfe rff rfm rfr rfs rft rme rmf rmm rmr rms rmt rrf rrm rrr rrs rrt rse rsf rsm rsr rss rst rte rtf rtm rtr rts rtt se- see sef sem ser ses set sfe sff sfm sfr sfs sft sme smf smm smr sms smt sr- sre srf srm srr srs srt ss- sse ssf ssm ssr sss sst ste stf stm str sts stt te- tee tef tem ter tes tet tfe tff tfm tfr tfs tft tme tmf tmm tmr tms tmt tre trf trm trr trs trt tse tsf tsm tsr tss tst tte ttf ttm ttr tts ttt