-er c-- ccc cce ccf ccg cco ccr ce- cec cee cef ceg ceo cer cfc cfe cff cfg cfo cfr cgc cge cgg cgo cgr co- coc coe cof cog coo cor crc cre crf crg cro crr ec- ecc ece ecf ecg eco ecr eec eee eef eeg eeo eer ef- efc efe eff efg efo efr egc ege egf egg ego egr eo- eoc eoe eof eog eoo eor erc ere erf erg ero err fcc fce fcf fcg fco fcr fec fee fef feg feo fer ffc ffe fff ffg ffo ffr fgc fge fgf fgg fgr foc foe fof fog foo for frc fre frf frg fro frr gcc gce gcf gcg gco gcr ge- gec gee gef geg geo ger gfc gfe gff gfo gfr ggc ggg ggo ggr goc goe gof gog goo gor grc gre grf grg gro grr oc- occ ocf ocg oco ocr oec oee oef oeg oeo oer of- ofc ofe off ofg ofo ofr ogc oge ogf ogg ogo oo- ooc oof oog ooo oor or- orc ore orf org oro orr rcc rce rcf rcg rco rcr re- rec ree ref reg reo rer rfc rfe rff rfg rfo rfr rgc rge rgf rgg rgo rgr roc roe rof rog roo ror rrc rrf rrg rrr