-er eee eem eer ees eet eex em- eme emm emr ems emt emx ere erm err ers ert es- ese esm esr ess est esx ete etm etr ets ett etx ex- exe exr exs ext exx m-r mee mem mer mes met mex mme mmm mmr mms mmt mmx mre mrm mrr mrs mrt mrx mse msm msr mss mst msx mte mtm mtr mts mtt mtx mxr mxs re- ree rem rer res ret rex rme rmm rmr rms rmt rmx rrm rrr rrs rrt rse rsm rsr rss rst rsx rte rtm rtr rts rtt rtx rxr rxs se- see sem ser ses set sex sme smm smr sms smt smx sr- sre srm srr srs srt srx ss- sse ssm ssr sss sst ssx ste stm str sts stt stx sxm sxs sxt t-x te- tee tem ter tes tet tex tme tmm tmr tms tmt tmx tre trm trr trs trt trx tse tsm tsr tss tst tsx tte ttm ttr tts ttt ttx txe txs txt xee xem xer xes xet xex xmm xmr xms xmt xmx xrt xrx xsm xss xst xtm xtr xts xtx xxx