-er eee eef eer eet ef- efe eff efr eft ere erf err ert ete etf etr ett fee fef fer fet ffe fff ffr fft fre frf frr frt fte ftf ftr ftt re- ree ref rer ret rfe rff rfr rft rrf rrr rrt rte rtf rtr rtt te- tee tef ter tet tfe tff tfr tft tre trf trr trt tte ttf ttr ttt

eeee eefe eete efet eft- erer eret erft erre etee eter etfe etre ette feer feet fefe feff fere ferr fert fete fetr fett ffee ffff ffrr fftf free fret fter reef reet refe reff refr reft rere rert rete retr rett rfef rrrr rtee teef teer teet teff teft ter- tere terf terr tete tetr tett tre- tree tref tret trfr trte trtr tter ttff tttt

-tree eeeee efere efetf effer effet efter erere erte erter etete etree etter feere feret ferr- ferre ferte feter fette freer freet frere frett ftrtt reefe reeft reere refer refet reffe rere- reree reret retee reter rette tefe teret terre tert- teter tetr- tette treer treet trefe treff trere trete trett ttttt

effere effete efreet efter- errett ferfer ferrer ferret fertee ferter fetter frefre frette fterer fterre r-tree reefer reeffe refeet refeff refert refete refret refter reteer reteet retere retree retret retter t-tree teetee teeter terete terrer terret terter tertre tetete tetter treete trefet trefte tretee trette

ferrere freeter fretter referee referer refrete rerefer reteere reterre retrete rettert terere terreer terrere tettete treetee trettre

ferreter ferrette fetterer referree referrer treefree