spp spr sps spt spx sr- srd sre srf sri srl sro srp srr srs srt srx ss- ssd sse ssf ssi ssl sso ssp ssr sss sst ssx std ste stf sti stl sto stp str sts stt stx sxi sxl sxs sxt t-x tdd tde tdf tdi tdl tdo tdp tdr tds tdt tdx te- ted tee tef tei tel teo tep ter tes tet tex tfd tfe tff tfi tfl tfo tfp tfr tfs tft tfx tid tie tif tii til tio tip tir tis tit tix tld tle tlf tli tll tlo tlp tlr tls tlt tlx to- tod toe tof toi tol too top tor tos tot tox tpd tpe tpf tpi tpl tpo tpp tpr tps tpt tpx trd tre trf tri trl tro trp trr trs trt trx tsd tse tsf tsi tsl tso tsp tsr tss tst tsx ttd tte ttf tti ttl tto ttp ttr tts ttt ttx txe txf txi txl txs txt xde xdf xdi xdr xds xdt xed xee xel xep xer xes xet xex xfe xfl xfs xft xfx xie xii xio xis xit xix xld xlf xli xlr xls xlt xod xof xoi xoo xop xor xos xot xox xpd xpe xpf xpl xpo xpp xps xpt xrd xrf xrt xrx xsi xsl xsp xss xst xtf xti xtp xtr xts xtx xxi xxl xxo xxp xxx