-tree e-ten eeeee eener eenet eepee eeten enent enete ennet enper enten enter entre epeen epene ereen erept erere ernen ernet erte erter etern etete etnre etree etten etter n-p-n neere nente neper neppe nepte neree neret nerre nerte neten netne nette ntete p-n-p p-rep peene peent peere peert peete pene- pener penne penre pent- pente pepee peppe pept- peren perer peret perne pernt perre perte peter petr- petre pette pptnt preen prene prent prepn prete prntr pter- ptere ptpre ptprn ptprr ptprt reene reepe reere renee rener renet renne rente repen repet reppe reprt rere- reree reret retee reter retnr rette rnpep rtenn teepe tenen tener tenet tenne tenpn tente tepee tepet teret terne terre tert- teten teter tetr- tette tntnt treen treer treet trene trent trepp trept trere trete trett ttnet ttttt