-er c-- ccc cce cco ccr ccs cct ce- cec cee ceo cer ces cet co- coc coe coo cor cos cot crc cre cro crr crs crt csc cse cso csr css cst ctc cte cto ctr cts ctt ec- ecc ece eco ecr ecs ect eec eee eeo eer ees eet eo- eoc eoe eoo eor eos eot erc ere ero err ers ert es- esc ese eso esr ess est etc ete eto etr ets ett oc- occ oco ocr ocs oct oec oee oeo oer oes oet oo- ooc ooo oor oos oot or- orc ore oro orr ors ort os- osc ose oso osr oss ost ot- otc ote oto otr ots ott rcc rce rco rcr rcs rct re- rec ree reo rer res ret roc roe roo ror ros rot rrc rrr rrs rrt rsc rse rso rsr rss rst rtc rte rto rtr rts rtt scc sce sco scr scs sct se- sec see seo ser ses set soc soe soo sor sos sot sr- src sre sro srr srs srt ss- ssc sse sso ssr sss sst stc ste sto str sts stt tcc tce tco tcr tcs tct te- tec tee teo ter tes tet to- toc toe too tor tos tot trc tre tro trr trs trt tsc tse tso tsr tss tst ttc tte tto ttr tts ttt