-er c-- ccc cce cck ccp ccr ccs ce- cec cee cek cep cer ces ckc cks cpc cpe cpk cpp cpr cps crc cre crk crp crr crs csc cse csk csp csr css ec- ecc ece eck ecr ecs eec eee eek eep eer ees ekc eke ekp ekr eks ep- epc epe epp epr eps erc ere erk erp err ers es- esc ese esk esp esr ess kcc kce kck kcp kcr kcs ke- kec kee kek kep ker kes kkc kke kkk kkp kkr kks kpc kpe kpk kpp kpr kps krc krk krp krr krs ksc kse ksk ksp ksr kss p-p pcc pce pck pcp pcr pcs pec pee pek pep per pes pkc pke pkp pkr pks ppc ppe ppk ppp ppr pps prc pre prk prp prr prs ps- psc pse psk psp psr pss rcc rce rcp rcr rcs re- rec ree rek rep rer res rkc rke rkk rkp rks rpc rpe rpk rpp rpr rps rrc rrk rrp rrr rrs rsc rse rsk rsp rsr rss scc sce sck scp scr scs se- sec see sek sep ser ses sk- skc ske skk skp skr sks spc spe spk spp spr sps sr- src sre srk srp srr srs ss- ssc sse ssk ssp ssr sss