a-fu aaaa aaab aaaf aaar aaba aabb aafa aafb aaff aara aaru abaa abab abaf abar abau abb- abba abbb abbr abff abra abua abuf afaa afar affa afr- afra afru afua arab araf arar arau arba arfa arfb arff arfu arr- arra arrr arru arua arub auaa aur- aura baaa baaf baar baba babb babr babu baff bar- bara barb barf barr baru bau- bauf baur bbau bbbb brab braf brau brfu brrr buar buba bubb bubu buff bufr bur- bura burb burr buru faaa faba fabu fafa faff fara farb farr faru faur fbar ffar ffff ffrr frab frau frub fuar fubb fubu fuff fufu fur- fura furr raab raaf raba rabb rabu rafa raff rara rarb rarf raua raub rauf rbaf rbbb rbbr rrrr ruba rubb rubu rufa ruff rura ruru uafa uaru uaua ubar ubba ubra uffa ufra urau urba urfa urff urra urur uuuu