-er c-- ccc cce ccr ccs cct ce- cec cee cer ces cet crc cre crr crs crt csc cse csr css cst ctc cte ctr cts ctt ec- ecc ece ecr ecs ect eec eee eer ees eet erc ere err ers ert es- esc ese esr ess est etc ete etr ets ett rcc rce rcr rcs rct re- rec ree rer res ret rrc rrr rrs rrt rsc rse rsr rss rst rtc rte rtr rts rtt scc sce scr scs sct se- sec see ser ses set sr- src sre srr srs srt ss- ssc sse ssr sss sst stc ste str sts stt tcc tce tcr tcs tct te- tec tee ter tes tet trc tre trr trs trt tsc tse tsr tss tst ttc tte ttr tts ttt