a-a a-c a-t aaa aac aae aaf aao aap aas aat aax ac- aca acc ace acf aco acp acs act acx aea aec aee aef aeo aep aes aet aex af- afa afc afe aff afo afp afs aft afx aoa aoc aoe aof aoo aop aos aot aox ap- apa apc ape apf apo app aps apt apx as- asa asc ase asf aso asp ass ast asx at- ata atc ate atf ato atp ats att atx ax- axa axe axo axp axs axt axx c-- caa cac cae caf cao cap cas cat cax cca ccc cce ccf cco ccp ccs cct ccx ce- cea cec cee cef ceo cep ces cet cex cfa cfc cfe cff cfo cfp cfs cft cfx co- coa coc coe cof coo cop cos cot cox cpa cpc cpe cpf cpo cpp cps cpt cpx csa csc cse csf cso csp css cst csx cta ctc cte ctf cto ctp cts ctt ctx cxc cxf cxo cxp cxs cxt cxx eaa eac eae eaf eao eap eas eat eax ec- eca ecc ece ecf eco ecs ect ecx eea eec eee eef eeo eep ees eet eex ef- efa efc efe eff efo efp efs eft efx eo- eoa eoc eoe eof eoo eop eos eot ep- epa epc epe epf epo epp eps ept epx es- esa esc ese esf eso esp ess est esx eta etc ete etf eto etp ets ett etx ex- exa exc exe exo exp exs ext exx faa fac fae faf fao fap fas fat fax fca fcc fce fcf fco fcp fcs fct fcx fea fec fee fef feo fep fes fet fex ffa ffc ffe fff ffo ffp ffs fft ffx foa foc foe fof foo fop fos fot fox fpa fpc fpe fpo fpp fps fpt fpx fsa fsc fse fsf fso fsp fss fst fsx fta ftc fte ftf fto ftp fts ftt ftx fxe fxp fxs fxt fxx oaa oac oae oaf oao oap oas oat oax oc- oca occ ocf oco ocp ocs oct ocx oea oec oee oef oeo oep oes oet oex of- ofa ofc ofe off ofo ofp ofs oft ofx oo- ooa ooc oof ooo oop oos oot oox op- opa opc ope opf opo opp ops opt opx os- osa osc ose osf oso osp oss ost osx ot- ota otc ote otf oto otp ots ott ox- oxa oxc oxf oxo oxt oxx p-p paa pac pae paf pao pap pas pat pax pca pcc pce pcf pco pcp pcs pct pcx pea pec pee pef peo pep pes pet pex pfa pfc pfe pff pfo pfp pfs pft pfx poa poc poe pof poo pop pos pot pox ppa ppc ppe ppf ppo ppp pps ppt ppx ps- psa psc pse psf pso psp pss pst psx pt- pta ptc pte ptf pto ptp pts ptt ptx pxc pxe pxs pxt saa sac sae saf sao sap sas sat sax sca scc sce scf sco scp scs sct scx se- sea sec see sef seo sep ses set sex sfa sfc sfe sff sfo sfp sfs sft sfx soa soc soe sof soo sop sos sot sox spa spc spe spf spo spp sps spt spx ss- ssa ssc sse ssf sso ssp sss sst ssx sta stc ste stf sto stp sts stt stx sxc sxs sxt t-x taa tac tae taf tao tap tas tat tax tca tcc tce tcf tco tcp tcs tct tcx te- tea tec tee tef teo tep tes tet tex tfa tfc tfe tff tfo tfp tfs tft tfx to- toa toc toe tof too top tos tot tox tpa tpc tpe tpf tpo tpp tps tpt tpx tsa tsc tse tsf tso tsp tss tst tsx tta ttc tte ttf tto ttp tts ttt ttx txe txf txs txt xaa xac xaf xap xas xat xcf xcp xcx xee xep xes xet xex xfa xfe xfs xft xfx xoa xoc xof xoo xop xos xot xox xpa xpc xpe xpf xpo xpp xps xpt xsa xsc xsp xss xst xtc xtf xtp xts xtx xxo xxp xxx