-er c-- ccc cce ccn ccr ccs ccx ce- cec cee cen cer ces cex cn- cnc cne cnn cnr cns cnx crc cre crn crr crs crx csc cse csn csr css csx cxc cxr cxs cxx ec- ecc ece ecn ecr ecs ecx eec eee een eer ees eex en- enc ene enn enr ens erc ere ern err ers es- esc ese esn esr ess esx ex- exc exe exr exs exx ncc nce ncn ncr ncs ncx ne- nec nee nen ner nes nex nnc nne nnn nns nrc nre nrn nrr nrs nrx nsc nse nsn nsr nss nsx nxc rcc rce rcn rcr rcs rcx re- rec ree ren rer res rex rnc rnn rnr rns rrc rrn rrr rrs rsc rse rsn rsr rss rsx rxr rxs scc sce scn scr scs scx se- sec see sen ser ses sex snc sne snn snr sns sr- src sre srn srr srs srx ss- ssc sse ssn ssr sss ssx sxc sxn sxs xcr xcx xee xen xer xes xex xnc xns xrc xrx xsc xss xxx