a-a a-c aaa aac aae aap aas aax ac- aca acc ace acp acs acx aea aec aee aep aes aex ap- apa apc ape app aps apx as- asa asc ase asp ass asx ax- axa axe axp axs axx c-- caa cac cae cap cas cax cca ccc cce ccp ccs ccx ce- cea cec cee cep ces cex cpa cpc cpe cpp cps cpx csa csc cse csp css csx cxc cxp cxs cxx eaa eac eae eap eas eax ec- eca ecc ece ecs ecx eea eec eee eep ees eex ep- epa epc epe epp eps epx es- esa esc ese esp ess esx ex- exa exc exe exp exs exx p-p paa pac pae pap pas pax pca pcc pce pcp pcs pcx pea pec pee pep pes pex ppa ppc ppe ppp pps ppx ps- psa psc pse psp pss psx pxc pxe pxs saa sac sae sap sas sax sca scc sce scp scs scx se- sea sec see sep ses sex spa spc spe spp sps spx ss- ssa ssc sse ssp sss ssx sxc sxs xaa xac xap xas xcp xcx xee xep xes xex xpa xpc xpe xpp xps xsa xsc xsp xss xxp xxx