a-be aaaa aaab aaac aaae aaaf aaba aabb aabc aaca aacb aacc aace aacf aaco aaea aaec aafa aafb aafc aaff aaoe aaoo abaa abab abac abae abaf abb- abba abbb abbe abbo abca abcb abcc abcf abec abee abff aboa abob abof aboo acaa acab acac acae acba acca accc acce accf acco ace- acea acec acfc acfe acoa acoe aeac aeaf aecb afaa afao afca afcb afcc afee affa affc affo afoa afoe afoo aoba aoca aoce baaa baaf baba babb babe babo bac- baca bacc bace baco bafc baff bafo bbbb bbeb bbfc bcaa bcbc bcca bccc bcec bcfc bcof beaf beba bebb bebe bebo beca beeb beef befa befe beff befo beo- beof bfca boab boac boba bobb bobe bobo boca boce boco boea boec boee boef boeo bofa bofe boff boob booc booe boof c-bo caaa caab caac caaf caba cabe cabf cabo cac- caca cacc cace caco caec cafa cafb cafc cafe caff cbac cbbc cbca cbcc cbce cbea cbec cbee cbef cbfb cbfc ccaa ccab ccac ccaf ccba ccbc ccca cccb cccc cccf ccee ccfa ccfc ccff ccob ccoc ceac ceba cec- ceca cece ceco ceeb ceec cef- cefa cefc cfaa cfab cfac cfae cfao cfbc cfca cfcb cfcf cfco cffb cfoa coba cobb cobe cobo coca coce coco cofc cofe coff coob coof eaaf eaba eaca eacc eaec eafb ebac ebba ebbc ebbo ebcc ebfc eboe eboo ecaa ecac ecao ecbc ecbe ecca eccb eccc ecce ecco ecef ecfa ecfc eco- eeca eeea eeee eefa eefe eeoc efab efca efco efeo effa faaa faac faba fabe fabo faca facc face faeb fafa fafc fafe faff fafo fcab fcba fcca fccf feaf feba febo fece feeb fefc fefe feff fefo feof ffcc ffee ffff foaf foba foca foce foco fofo foof o-eo oafc oafo obba obbo obea obec oboe ocab ocac ocbc occa occc oce ocee ocef ocfa oec- oeca oecc oeec off- offa offc offe offo ooaa ooba oobe ooff oooo