-er c-- ccc cce cco ccp ccr ccs ccx ce- cec cee ceo cep cer ces cex co- coc coe coo cop cor cos cox cpc cpe cpo cpp cpr cps cpx crc cre cro crp crr crs crx csc cse cso csp csr css csx cxc cxo cxp cxr cxs cxx ec- ecc ece eco ecr ecs ecx eec eee eeo eep eer ees eex eo- eoc eoe eoo eop eor eos ep- epc epe epo epp epr eps epx erc ere ero erp err ers es- esc ese eso esp esr ess esx ex- exc exe exo exp exr exs exx oc- occ oco ocp ocr ocs ocx oec oee oeo oep oer oes oex oo- ooc ooo oop oor oos oox op- opc ope opo opp opr ops opx or- orc ore oro orp orr ors orx os- osc ose oso osp osr oss osx ox- oxc oxo oxx p-p pcc pce pco pcp pcr pcs pcx pec pee peo pep per pes pex poc poe poo pop por pos pox ppc ppe ppo ppp ppr pps ppx prc pre pro prp prr prs prx ps- psc pse pso psp psr pss psx pxc pxe pxr pxs rcc rce rco rcp rcr rcs rcx re- rec ree reo rep rer res rex roc roe roo rop ror ros rox rpc rpe rpo rpp rpr rps rpx rrc rrp rrr rrs rsc rse rso rsp rsr rss rsx rxp rxr rxs scc sce sco scp scr scs scx se- sec see seo sep ser ses sex soc soe soo sop sor sos sox spc spe spo spp spr sps spx sr- src sre sro srp srr srs srx ss- ssc sse sso ssp ssr sss ssx sxc sxs xcp xcr xcx xee xep xer xes xex xoc xoo xop xor xos xox xpc xpe xpo xpp xps xrc xrx xsc xsp xss xxo xxp xxx