a-a a-c aaa aac aae aap aax ac- aca acc ace acp acx aea aec aee aep aex ap- apa apc ape app apx ax- axa axe axp axx c-- caa cac cae cap cax cca ccc cce ccp ccx ce- cea cec cee cep cex cpa cpc cpe cpp cpx cxc cxp cxx eaa eac eae eap eax ec- eca ecc ece ecx eea eec eee eep eex ep- epa epc epe epp epx ex- exa exc exe exp exx p-p paa pac pae pap pax pca pcc pce pcp pcx pea pec pee pep pex ppa ppc ppe ppp ppx pxc pxe xaa xac xap xcp xcx xee xep xex xpa xpc xpe xpp xxp xxx