a-fu aaaa aaab aaac aaaf aaal aaba aabb aabc aabl aaca aacb aacc aacf aacl aacu aafa aafb aafc aaff aafl aala aalc aall aalu abaa abab abac abaf abal abau abb- abba abbb abca abcb abcc abcf abcl abff abla abua abuf abul acaa acab acac acba acbl acca accc accf accu acfc acfl acla aclc aclu acu- acuf acul afaa afca afcb afcc afcu affa affc afla aflc afua alaa alac alal alau alb- alba albc albu alca alcc alfa all- alla alll allu alua aluf auaa auca aufc aul- aula aulf aull aulu baaa baaf baal baba babb babu bac- baca bacc bafc baff bala balc balf ball balu bau- bauf baul bbau bbbb bbfc bblb bcaa bcbc bcca bccc bccl bcfc bcuc bfca bffl blaa blab blac blau blcu blfc blub bluf bual buba bubb bubu buca bucc bucu bufc buff bula bulb bull bulu caaa caab caac caaf caal caba cabf cabu cac- caca cacc cafa cafb cafc caff cafl cafu cala calc calf call calu cauc cauf caul cbac cbal cbbc cbca cbcc cbcl cbcu cbfb cbfc cblb cblc ccaa ccab ccac ccaf ccba ccbc ccca cccb cccc cccf cccl cccu ccfa ccfc ccff ccfl ccla cclc ccuc cfaa cfab cfac cfbc cfca cfcb cfcf cfcl cffb clab claf clau club cuau cub- cuba cubb cuca cucc cufa cufc cuff cula culb culc cull faaa faac faba fabu faca facc fafa fafc faff fala falc fall falu faul fbla fcab fcal fcba fcca fccf ffcc ffff flab flac flcl flub fluf fubb fubu fuc- fuca fufc fuff fufu fula full fulu laaa laac laal laba labu laca lacc lacl lacu lafb lafc laff lala lall lalu laub lauf laul lbcc lcac lcbc lcca lccc lcfc lfca lfcc llcc lllc llll luau luba luca luff lufu lula lull lulu luua uabc uaca uafa uaua ubac ubal ubba ubla ucal ucbc ucca ucfa ucfb ucla ucua ufcu uffa ulaa ulbc ulcc ulla ulua ulul uulu uuuu