-er bbb bbe bbg bbo bbr bbt be- beb bee beg beo ber bet bgb bge bgg bgo bgr bgt bob boe bog boo bor bot brb bre brg bro brr brt btb bte btg bto btr btt ebb ebe ebg ebo ebr ebt eeb eee eeg eeo eer eet egb ege egg ego egr egt eo- eob eoe eog eoo eor eot erb ere erg ero err ert etb ete etg eto etr ett gbe gbg gbo gbr gbt ge- geb gee geg geo ger get ggb ggg ggo ggr ggt gob goe gog goo gor got grb gre grg gro grr grt gtb gte gtg gto gtr gtt ob- obb obe obg obo obr obt oeb oee oeg oeo oer oet oge ogg ogo ogt oo- oob oog ooo oor oot or- orb ore org oro orr ort ot- otb ote otg oto otr ott rbb rbe rbg rbo rbr rbt re- reb ree reg reo rer ret rgb rge rgg rgo rgr rgt rob roe rog roo ror rot rrb rrg rrr rrt rtb rte rtg rto rtr rtt tbb tbe tbg tbo tbr tbt te- teb tee teg teo ter tet tgb tge tgg tgo tgr tgt to- tob toe tog too tor tot trb tre trg tro trr trt ttb tte ttg tto ttr ttt