-er bbb bbe bbl bbn bbr bbx be- beb bee bel ben ber bex blb ble bll bln blr blx bnb bne bnl bnn bnr bnx brb bre brl brn brr brx bxb bxl bxn bxx ebb ebe ebl ebn ebr ebx eeb eee eel een eer eex elb ele ell eln elr elx en- enb ene enl enn enr erb ere erl ern err ex- exe exl exr exx lbb lbe lbl lbr lbx leb lee lel len ler lex llb lle lll lln llr lnb lne lnl lnn lnr lrb lrn lrr lxr lxx nbb nbe nbl nbn nbr nbx ne- neb nee nel nen ner nex nlb nle nll nln nlr nlx nnb nne nnl nnn nrb nre nrl nrn nrr nrx nxl rbb rbe rbl rbn rbr rbx re- reb ree rel ren rer rex rle rll rln rlr rnb rnn rnr rrb rrl rrn rrr rxr xbe xbl xbr xbx xee xel xen xer xex xlb xlr xrx xxl xxx