-er c-- ccc cce ccg cco ccr ccv ce- cec cee ceg ceo cer cev cgc cge cgg cgo cgr cgv co- coc coe cog coo cor cov crc cre crg cro crr crv cvc cve cvg cvo cvr cvv ec- ecc ece ecg eco ecr ecv eec eee eeg eeo eer eev egc ege egg ego egr eo- eoc eoe eog eoo eor erc ere erg ero err erv evc eve evg evo evr evv gcc gce gcg gco gcr ge- gec gee geg geo ger gev ggc ggg ggo ggr ggv goc goe gog goo gor gov grc gre grg gro grr grv gvc gve gvg gvo gvr oc- occ ocg oco ocr ocv oec oee oeg oeo oer ogc oge ogg ogo oo- ooc oog ooo oor oov or- orc ore org oro orr orv ov- ovc ove ovo ovv rcc rce rcg rco rcr rcv re- rec ree reg reo rer rev rgc rge rgg rgo rgr rgv roc roe rog roo ror rov rrc rrg rrr rvc rve rvg rvo rvr rvv v-e vcc vce vco vcr vec vee veg veo ver vgc vgg vgo vgr voc voe vog voo vor vov vrc vre vrg vrr vvc vvg vvo vvr vvv