-er bbb bbe bbg bbn bbo bbr bbx be- beb bee beg ben beo ber bex bgb bge bgg bgn bgo bgr bgx bnb bne bng bnn bno bnr bnx bob boe bog bon boo bor box brb bre brg brn bro brr brx bxb bxn bxo bxx ebb ebe ebg ebn ebo ebr ebx eeb eee eeg een eeo eer eex egb ege egg egn ego egr egx en- enb ene eng enn eno enr eo- eob eoe eog eon eoo eor erb ere erg ern ero err ex- exe exo exr exx gbe gbg gbn gbo gbr gbx ge- geb gee geg gen geo ger gex ggb ggg ggn ggo ggr gnb gne gnn gno gnr gob goe gog gon goo gor gox grb gre grg grn gro grr grx nbb nbe nbg nbn nbo nbr nbx ne- neb nee neg nen neo ner nex ngb nge ngg ngn ngo nnb nne nng nnn nno no- nob noe nog non noo nor nox nrb nre nrg nrn nro nrr nrx ob- obb obe obg obn obo obr obx oeb oee oeg oen oeo oer oex oge ogg ogn ogo ogx on- onb one ong onn ono onr onx oo- oob oog oon ooo oor oox or- orb ore org orn oro orr orx ox- oxb oxn oxo oxx rbb rbe rbg rbn rbo rbr rbx re- reb ree reg ren reo rer rex rgb rge rgg rgn rgo rgr rgx rnb rng rnn rno rnr rob roe rog ron roo ror rox rrb rrg rrn rrr rxr xbe xbr xbx xee xeg xen xer xex xge xno xog xon xoo xor xox xrx xxo xxx