b-tree bbbbbb beebee beerne beeter benben benete benett benner bennet bentee benter berbee berber bereet berene berere berner berrer berret bertre betere betete bettee betten better breere brener brenne brette ebbert eebree enbene enteer entent enter- entere entete entre- entree entrer erbent erbree erenet ernee errett eterne nberet nebber neener nerrer netter r-tree rebent renner rennet renren rentee renter rerent reteer reteet retene retent retere retree retret retter t-tree teebee teener teetee teeter tenent tenner tennet tenten tenter tereen terene terete terner terren terrer terret terter tertre tetete tetter tntnet treben treene treete trenet trenne trente tretee trette ttrent