-er b-u bbb bbe bbk bbr bbt bbu be- beb bee bek ber bet beu bkb bke bkk bkr bkt brb bre brk brr brt bru btb bte btk btr btt btu bub bue buk bur but buu ebb ebe ebk ebr ebt ebu eeb eee eek eer eet ekb eke ekr ekt eku erb ere erk err ert eru etb ete etk etr ett etu eu- eub eue eur eut k-t kbb kbe kbk kbr kbu ke- keb kee kek ker ket kkb kke kkk kkr kkt kku krk krr krt kru ktb kte ktk ktr ktt ktu kub kue kuk kur kut kuu rbb rbe rbk rbr rbt rbu re- reb ree rek rer ret reu rkb rke rkk rkt rku rrb rrk rrr rrt rru rtb rte rtk rtr rtt rtu rub rue ruk rur rut ruu tbb tbe tbk tbr tbt tbu te- teb tee tek ter tet teu tkb tke tkk tkr tkt trb tre trk trr trt tru ttb tte ttk ttr ttt ttu tub tue tuk tur tut tuu ubb ube ubk ubr ubt ubu ueb uee uer uet ukb uke ukk ukr uku ur- urb ure urk urr urt uru utb ute utk utr utt utu uue uur uut uuu