-er bbb bbe bbi bbl bbr bbx be- beb bee bei bel ber bex bi- bib bie bii bil bir bix blb ble bli bll blr blx brb bre bri brl brr brx bxb bxi bxl bxx ebb ebe ebi ebl ebr ebx eeb eee eel eer eex eib eie eii eil eir eix elb ele eli ell elr elx erb ere eri erl err ex- exe exi exl exr exx ibb ibe ibi ibl ibr ibx ie- iee iei iel ier iex iib iie iii iil iir iix il- ilb ile ili ill ilr ilx ir- irb ire iri irl irr irx ixe ixi ixl lbb lbe lbi lbl lbr lbx leb lee lei lel ler lex lib lie lii lil lir lix llb lle lli lll llr lrb lri lrr lxi lxr lxx rbb rbe rbi rbl rbr rbx re- reb ree rei rel rer rex rib rie rii ril rir rix rle rli rll rlr rrb rri rrl rrr rxr xbe xbl xbr xbx xee xel xer xex xie xii xix xlb xli xlr xrx xxi xxl xxx