-er c-- ccc cce ccf cco ccr cct ce- cec cee cef ceo cer cet cfc cfe cff cfo cfr cft co- coc coe cof coo cor cot crc cre crf cro crr crt ctc cte ctf cto ctr ctt ec- ecc ece ecf eco ecr ect eec eee eef eeo eer eet ef- efc efe eff efo efr eft eo- eoc eoe eof eoo eor eot erc ere erf ero err ert etc ete etf eto etr ett fcc fce fcf fco fcr fct fec fee fef feo fer fet ffc ffe fff ffo ffr fft foc foe fof foo for fot frc fre frf fro frr frt ftc fte ftf fto ftr ftt oc- occ ocf oco ocr oct oec oee oef oeo oer oet of- ofc ofe off ofo ofr oft oo- ooc oof ooo oor oot or- orc ore orf oro orr ort ot- otc ote otf oto otr ott rcc rce rcf rco rcr rct re- rec ree ref reo rer ret rfc rfe rff rfo rfr rft roc roe rof roo ror rot rrc rrf rrr rrt rtc rte rtf rto rtr rtt tcc tce tcf tco tcr tct te- tec tee tef teo ter tet tfc tfe tff tfo tfr tft to- toc toe tof too tor tot trc tre trf tro trr trt ttc tte ttf tto ttr ttt