-er bbb bbc bbe bbk bbl bbn bbr bcb bcc bce bck bcl bcn bcr be- beb bec bee bek bel ben ber bkb bkc bke bkk bkl bkn bkr blb blc ble blk bll bln blr bnb bnc bne bnk bnl bnn bnr brb bre brk brl brn brr c-- cbb cbc cbe cbk cbl cbn cbr ccb ccc cce cck ccl ccn ccr ce- ceb cec cee cek cel cen cer ckb ckc cl- clb clc cle clk cll cln clr cn- cnb cnc cne cnl cnn cnr crb crc cre crk crl crn crr ebb ebc ebe ebk ebl ebn ebr ec- ecb ecc ece eck ecl ecn ecr eeb eec eee eek eel een eer ekb ekc eke ekl ekr elb elc ele elk ell eln elr en- enb enc ene enk enl enn enr erb erc ere erk erl ern err kbb kbc kbe kbk kbl kbn kbr kcb kcc kce kck kcl kcn kcr ke- keb kec kee kek kel ken ker kkb kkc kke kkk kkl kkn kkr kl- klb klc klr kn- knc kne knk knl knn knr krc krk krl krn krr lbb lbc lbe lbk lbl lbr lcb lcc lce lck lcl lcn lcr leb lec lee lek lel len ler lkb lkl lkr llb llc lle llk lll lln llr lnb lnc lne lnk lnl lnn lnr lrb lrc lrk lrn lrr nbb nbc nbe nbk nbl nbn nbr ncb ncc nce nck ncl ncn ncr ne- neb nec nee nek nel nen ner nkc nke nkk nkn nkr nlb nlc nle nlk nll nln nlr nnb nnc nne nnk nnl nnn nrb nrc nre nrk nrl nrn nrr rbb rbc rbe rbk rbl rbn rbr rcb rcc rce rcl rcn rcr re- reb rec ree rek rel ren rer rkb rkc rke rkk rlc rle rll rln rlr rnb rnc rnn rnr rrb rrc rrk rrl rrn rrr