-er bbb bbd bbe bbk bbn bbr bdb bdd bde bdk bdr be- beb bed bee bek ben ber bkb bke bkk bkn bkr bnb bnd bne bnk bnn bnr brb brd bre brk brn brr dbb dbd dbe dbk dbn dbr ddb ddd dde ddk ddn ddr de- deb ded dee dek den der dkb dke dkk dkr dnb dnd dne dnk dnn dnr drb drd dre drk drn drr ebb ebd ebe ebk ebn ebr ed- edb edd ede edk edn edr eeb eed eee eek een eer ekb ekd eke ekr en- enb end ene enk enn enr erb erd ere erk ern err kbb kbd kbe kbk kbn kbr kdb kde kdk kdr ke- keb ked kee kek ken ker kkb kke kkk kkn kkr kn- knd kne knk knn knr krd krk krn krr nbb nbd nbe nbk nbn nbr ndb ndd nde ndk ndn ndr ne- neb ned nee nek nen ner nke nkk nkn nkr nnb nne nnk nnn nrb nrd nre nrk nrn nrr rbb rbd rbe rbk rbn rbr rdb rdd rde rdn rdr re- reb red ree rek ren rer rkb rke rkk rnb rnd rnn rnr rrb rrd rrk rrn rrr