-ene bbbb bbeb bbet bbrc bcbc bccc bcec bcer bcet bctc bebb bebe beeb been beer beet bene benn bent berc bere bern berr bert betc bete bett bner bnet bnrr brcb brce breb brec bree bren brer bret brrr brtc btcc btec bten btrc btrt bttb cbbc cbcc cbce cbcn cbcr cbct cbec cbee cber cbet cbre cbrn cbrt cbtc ccbc ccbn cccb cccc ccee ccnb ccnc ccne ccnr ccrc ccre ccrt cctb cctc cctt cec- cece cect ceeb ceec cen- cene cent cer- cerc cere cern cert cet- cete cnbc cnet cnrc cnrr cnrt cntc cntr crbc crcc crce crcr cre- creb crec cree cren cret crne crrt crtc ctec cten ctne ctrc ctrn cttn ebbc ebbr ebcc eben eber ecbc ecbe eccb eccc ecce ecct ecne ecrc ecrr ect- ectc eeee eent eerc eetc eete enb- enbn enbr ence enee ener ennc enne ent- ente entr erbb erbe ercc erce ereb erec eren erer eret erne errc erre etbc etbr etcc etec etee eten eter etne etnr etre ette ettn nbbc nbcc nber ncbc nccc nccn nccr ncct ncec ncee ncen ncer ncnc ncrc ncre nctc ncte nctr nebb nebe nebn nebr necc nece necr nect neeb neen neer neet nene nent nerc nere nerr nert net- netb nete nett nnnn nntn nren nrrc ntbc ntcc nter ntrc nttr rbbb rbbr rcbc rccb rccc rcet rcnr rctc rebb rebe recc rece recr rect reeb reen reet rene renn rent rere rert rete retr rett rnbr rnnt rrrr rtcc rtce rtee tbcb tbcc tbce tbrb tccc tcnn tctc tecr tect teec teen teer teet tenb tenc tene tenn tent ter- terc tere tern terr tete tetr tett tnbc tncc tneb trcc tre- trec tree tren tret trtc trte trtr ttbb ttcn tten tter tttt