-er a-a a-b a-c aaa aab aac aae aaf aar aau ab- aba abb abc abe abf abr abu ac- aca acb acc ace acf acr acu aea aeb aec aee aef aer aeu af- afa afb afc afe aff afr afu ar- ara arb arc are arf arr aru au- aua aub auc aue auf aur b-u baa bab bac bae baf bar bau bba bbb bbc bbe bbf bbr bbu bca bcb bcc bce bcf bcr bcu be- bea beb bec bee bef ber beu bfa bfb bfc bfe bff bfr bfu bra brb bre brf brr bru bua bub buc bue buf bur buu c-- caa cab cac cae caf car cau cba cbb cbc cbe cbf cbr cbu cca ccb ccc cce ccf ccr ccu ce- cea ceb cec cee cef cer ceu cfa cfb cfc cfe cff cfr cfu cra crb crc cre crf crr cru cua cub cuc cue cuf cur cuu eaa eab eac eae eaf ear eau eba ebb ebc ebe ebf ebr ebu ec- eca ecb ecc ece ecf ecr ecu eea eeb eec eee eef eer ef- efa efb efc efe eff efr era erb erc ere erf err eru eu- eua eub euc eue euf eur faa fab fac fae faf far fau fba fbb fbc fbe fbf fbr fbu fca fcb fcc fce fcf fcr fcu fea feb fec fee fef fer feu ffa ffc ffe fff ffr ffu fra frb frc fre frf frr fru fua fub fue fuf fur fuu ra- raa rab rac rae raf rar rau rba rbb rbc rbe rbf rbr rbu rca rcb rcc rce rcf rcr rcu re- rea reb rec ree ref rer reu rfa rfb rfc rfe rff rfr rfu rra rrb rrc rrf rrr rru rua rub ruc rue ruf rur ruu ua- uaa uab uac uae uaf uar uau uba ubb ubc ube ubf ubr ubu uca ucb ucc uce ucf ucr ucu uea ueb uec uee uef uer ufa ufc ufe uff ufr ufu ur- ura urb urc ure urf urr uru uua uuc uue uur uuu

a-be a-fu aaaa aaab aaac aaae aaaf aaar aaba aabb aabc aaca aacb aacc aace aacf aacr aacu aaea aaec aafa aafb aafc aaff aara aarc aare aaru abaa abab abac abae abaf abar abau abb- abba abbb abbe abbr abca abcb abcc abcf abcr abec abee aber abff abra abrc abua abue abuf acaa acab acac acae acar acba acca accc acce accf accu ace- acea acec acer acfc acfe acr- acra acrc acre acrr acu- acue acuf acur aeac aeaf aecb aeer aer- aera aerc afaa afar afca afcb afcc afcu afee afer affa affc afr- afra afrc afre afru afua afue arab arac arae araf arar arau arba arbe arc- arca arce area arec aree aref areu arfa arfb arfc arff arfu arr- arra arrc arre arrr arru arua arub arue auaa aube auca auce auer aufc aufe aur- aura aure baaa baaf baar baba babb babe babr babu bac- baca bacc bace baer bafc baff bar- bara barb barc bare barf barr baru bau- bauf baur bbau bbbb bbeb bbfc bbrc bcaa bcar bcbc bcca bccc bcec bcer bcfc bcra bcru bcuc beaf bear beau beba bebb bebe beca becu beeb beef beer befa befe beff bera berc bere berr beru beur bfca brab brac brae braf brau brca brcb brce brea breb brec bree bref brer brfc brfu brrr bruc brue buar buba bubb bube bubu buca bucc buce bucu buea buer bueu bufc bufe buff bufr bur- bura burb bure burr buru caaa caab caac caaf caba cabe cabf cabu cac- caca cacc cace cacr caec caer caeu cafa cafb cafc cafe caff cafu cara carb carc care carf carr cauc cauf cbac cbar cbbc cbca cbcc cbce cbcr cbcu cbea cbec cbee cbef cber cbfb cbfc cbre ccaa ccab ccac ccaf ccar ccba ccbc ccca cccb cccc cccf cccu ccee ccfa ccfc ccff ccra ccrc ccre ccrf ccuc ceac cear ceba cebu cec- ceca cece ceeb ceec cef- cefa cefc cer- cera cerc cere cerf cfaa cfab cfac cfae cfar cfbc cfbr cfca cfcb cfcf cffb cffr cfra cfrb cfre crab crac craf crar crau crbc crbu crca crcc crce crcr cre- crea creb crec cree creu crfc crub crue cuau cub- cuba cubb cube cuca cucc cuce cuer cufa cufc cuff cura curb cure curf curr eaaf eaba eaca eacc eaec eafb eara earb eare ebac ebba ebbc ebbr ebcc eber ebfc ebru ebur ecaa ecac ecar ecbc ecbe ecca eccb eccc ecce ecef ecfa ecfc ecfr ecra ecrc ecrf ecrr ecru ecua eeca eeea eeee eefa eefe eera eerc efab efbr efca effa efua eraf erau erba erbb erbe erca ercc erce ereb erec erer erfc erra errc erre erua erub eruc erur euba eubc euer eufc eur- eura eurc eure faaa faac faba fabe fabu faca facc face faeb fafa fafc fafe faff fara farb farc fare farr faru faue faur fbar fcab fcar fcba fcca fccf fcra feaf fear feba fece feeb feer fefc fefe feff fera ferb ferc fere ferr feru ffar ffcc ffee ffff ffrr frab frac frae frau frbc frcc frea free frfc frub frue fuar fubb fubu fuc- fuca fufc fuff fufu fur- fura fure furr raab raaf raba rabb rabe rabu rac- raca racc race racu raec raef raer rafa rafc rafe raff rara rarb rare rarf raua raub rauc raue rauf rbaf rbbb rbbr rcac rcaf rcbc rccb rccc rcfc rea- reac reae reaf rear reau reba rebb rebe rebu reca recc rece recr recu reeb reef refe reff refr refu rera rere reru reue reuf reuu rfae rfef rffc rrfc rrrr ruba rubb rube rubu ruca ruce ruer rufa rufc rufe ruff rura rurc rure ruru uabc uaca uafa uarc uaru uaua ubac ubar ubba ubbe uber ubra ucar ucbc ucca ucea ucfa ucfb ucrc ucua ueba uefa ufcu ufer uffa uffe ufra urac urau urba urbe urca ure- urea urfa