-er c-- ccc cce cck ccr ccs cct ce- cec cee cek cer ces cet ckc cks ckt crc cre crk crr crs crt csc cse csk csr css cst ctc cte ctk ctr cts ctt ec- ecc ece eck ecr ecs ect eec eee eek eer ees eet ekc eke ekr eks ekt erc ere erk err ers ert es- esc ese esk esr ess est etc ete etk etr ets ett k-t kcc kce kck kcr kcs kct ke- kec kee kek ker kes ket kkc kke kkk kkr kks kkt krc krk krr krs krt ksc kse ksk ksr kss kst ktc kte ktk ktr kts ktt rcc rce rcr rcs rct re- rec ree rek rer res ret rkc rke rkk rks rkt rrc rrk rrr rrs rrt rsc rse rsk rsr rss rst rtc rte rtk rtr rts rtt scc sce sck scr scs sct se- sec see sek ser ses set sk- skc ske skk skr sks skt sr- src sre srk srr srs srt ss- ssc sse ssk ssr sss sst stc ste stk str sts stt tcc tce tck tcr tcs tct te- tec tee tek ter tes tet tkc tke tkk tkr tks tkt trc tre trk trr trs trt tsc tse tsk tsr tss tst ttc tte ttk ttr tts ttt