b-tree bbbbbb bedded bedder bedebt beebee beedee beerde beeter berbee berber berede bereet berere berrer berret bertre betere betete betted bettee better bredde breded breder breede breere brette dbette de-err debdeb debere debert debete debret debted debtee deeded deedee deeder derere derrer deterr detete detter dreder ebbert eebree erbree errett r-tree rebred redbed redded redder redere redred redted reeded reeder reteed reteer reteet retere retree retret retted retter t-tree tedded tedder teebee teeder teetee teeter terete terrer terret terter tertre tetede tetete tetter treder treete tretee trette