a-be aaaa aaab aaac aaae aaba aabb aabc aaca aacb aacc aace aacu aaea aaec abaa abab abac abae abau abb- abba abbb abbe abca abcb abcc abec abee abua abue acaa acab acac acae acba acca accc acce accu ace- acea acec acu- acue aeac aecb auaa aube auca auce baaa baba babb babe babu bac- baca bacc bace bau- bbau bbbb bbeb bcaa bcbc bcca bccc bcec bcuc beau beba bebb bebe beca becu beeb buba bubb bube bubu buca bucc buce bucu buea bueu caaa caab caac caba cabe cabu cac- caca cacc cace caec caeu cauc cbac cbbc cbca cbcc cbce cbcu cbea cbec cbee ccaa ccab ccac ccba ccbc ccca cccb cccc cccu ccee ccuc ceac ceba cebu cec- ceca cece ceeb ceec cuau cub- cuba cubb cube cuca cucc cuce eaba eaca eacc eaec ebac ebba ebbc ebcc ecaa ecac ecbc ecbe ecca eccb eccc ecce ecua eeca eeea eeee euba eubc uabc uaca uaua ubac ubba ubbe ucbc ucca ucea ucua ueba uuuu