-er bbb bbe bbk bbn bbr bbt be- beb bee bek ben ber bet bkb bke bkk bkn bkr bkt bnb bne bnk bnn bnr bnt brb bre brk brn brr brt btb bte btk btn btr btt ebb ebe ebk ebn ebr ebt eeb eee eek een eer eet ekb eke ekr ekt en- enb ene enk enn enr ent erb ere erk ern err ert etb ete etk etn etr ett k-t kbb kbe kbk kbn kbr ke- keb kee kek ken ker ket kkb kke kkk kkn kkr kkt kn- kne knk knn knr knt krk krn krr krt ktb kte ktk ktn ktr ktt nbb nbe nbk nbn nbr nbt ne- neb nee nek nen ner net nke nkk nkn nkr nkt nnb nne nnk nnn nnt nrb nre nrk nrn nrr nrt ntb nte ntk ntn ntr ntt rbb rbe rbk rbn rbr rbt re- reb ree rek ren rer ret rkb rke rkk rkt rnb rnn rnr rnt rrb rrk rrn rrr rrt rtb rte rtk rtn rtr rtt tbb tbe tbk tbn tbr tbt te- teb tee tek ten ter tet tkb tke tkk tkr tkt tnb tne tnk tnn tnr tnt trb tre trk trn trr trt ttb tte ttk ttn ttr ttt