-er c-- ccc cce cco ccr cct ce- cec cee ceo cer cet co- coc coe coo cor cot crc cre cro crr crt ctc cte cto ctr ctt ec- ecc ece eco ecr ect eec eee eeo eer eet eo- eoc eoe eoo eor eot erc ere ero err ert etc ete eto etr ett oc- occ oco ocr oct oec oee oeo oer oet oo- ooc ooo oor oot or- orc ore oro orr ort ot- otc ote oto otr ott rcc rce rco rcr rct re- rec ree reo rer ret roc roe roo ror rot rrc rrr rrt rtc rte rto rtr rtt tcc tce tco tcr tct te- tec tee teo ter tet to- toc toe too tor tot trc tre tro trr trt ttc tte tto ttr ttt