spc spe spf spi spn spo spp spr sps spt spx sr- src sre srf sri srn sro srp srr srs srt srx ss- ssc sse ssf ssi ssn sso ssp ssr sss sst ssx stc ste stf sti stn sto stp str sts stt stx sxc sxi sxn sxs sxt t-x tcc tce tcf tci tcn tco tcp tcr tcs tct tcx te- tec tee tef tei ten teo tep ter tes tet tex tfc tfe tff tfi tfn tfo tfp tfr tfs tft tfx tic tie tif tii tin tio tip tir tis tit tix tnc tne tnf tni tnn tno tnp tnr tns tnt tnx to- toc toe tof toi ton too top tor tos tot tox tpc tpe tpf tpi tpn tpo tpp tpr tps tpt tpx trc tre trf tri trn tro trp trr trs trt trx tsc tse tsf tsi tsn tso tsp tsr tss tst tsx ttc tte ttf tti ttn tto ttp ttr tts ttt ttx txe txf txi txn txs txt xcf xci xcp xcr xcx xee xen xep xer xes xet xex xfe xfn xfs xft xfx xic xie xii xin xio xis xit xix xnc xno xns xoc xof xoi xon xoo xop xor xos xot xox xpc xpe xpf xpn xpo xpp xps xpt xrc xrf xrt xrx xsc xsi xsp xss xst xtc xtf xti xtp xtr xts xtx xxi xxo xxp xxx