-er bbb bbe bbf bbg bbo bbr be- beb bee bef beg beo ber bfb bfe bff bfg bfo bfr bgb bge bgf bgg bgo bgr bob boe bof bog boo bor brb bre brf brg bro brr ebb ebe ebf ebg ebo ebr eeb eee eef eeg eeo eer ef- efb efe eff efg efo efr egb ege egf egg ego egr eo- eob eoe eof eog eoo eor erb ere erf erg ero err fbb fbe fbf fbg fbo fbr feb fee fef feg feo fer ffe fff ffg ffo ffr fgb fge fgf fgg fgr fob foe fof fog foo for frb fre frf frg fro frr gbe gbf gbg gbo gbr ge- geb gee gef geg geo ger gfb gfe gff gfo gfr ggb ggg ggo ggr gob goe gof gog goo gor grb gre grf grg gro grr ob- obb obe obf obg obo obr oeb oee oef oeg oeo oer of- ofb ofe off ofg ofo ofr oge ogf ogg ogo oo- oob oof oog ooo oor or- orb ore orf org oro orr rbb rbe rbf rbg rbo rbr re- reb ree ref reg reo rer rfb rfe rff rfg rfo rfr rgb rge rgf rgg rgo rgr rob roe rof rog roo ror rrb rrf rrg rrr