a-a a-c a-t aaa aac aae aan aap aat aax ac- aca acc ace acn acp act acx aea aec aee aen aep aet aex an- ana anc ane ann anp ant anx ap- apa apc ape apn app apt apx at- ata atc ate atn atp att atx ax- axa axe axn axp axt axx c-- caa cac cae can cap cat cax cca ccc cce ccn ccp cct ccx ce- cea cec cee cen cep cet cex cn- cna cnc cne cnn cnp cnt cnx cpa cpc cpe cpn cpp cpt cpx cta ctc cte ctn ctp ctt ctx cxc cxp cxt cxx eaa eac eae ean eap eat eax ec- eca ecc ece ecn ect ecx eea eec eee een eep eet eex en- ena enc ene enn enp ent ep- epa epc epe epn epp ept epx eta etc ete etn etp ett etx ex- exa exc exe exp ext exx naa nac nae nan nap nat nax nca ncc nce ncn ncp nct ncx ne- nea nec nee nen nep net nex nna nnc nne nnn nnp nnt npa npc npe npn npp npt nta ntc nte ntn ntp ntt ntx nxc nxt p-p paa pac pae pan pap pat pax pca pcc pce pcn pcp pct pcx pea pec pee pen pep pet pex pn- pna pnc pne pnn pnp pnt pnx ppa ppc ppe ppn ppp ppt ppx pt- pta ptc pte ptn ptp ptt ptx pxc pxe pxt t-x taa tac tae tan tap tat tax tca tcc tce tcn tcp tct tcx te- tea tec tee ten tep tet tex tna tnc tne tnn tnp tnt tnx tpa tpc tpe tpn tpp tpt tpx tta ttc tte ttn ttp ttt ttx txe txn txt xaa xac xan xap xat xcp xcx xee xen xep xet xex xna xnc xpa xpc xpe xpn xpp xpt xtc xtp xtx xxp xxx