a-ya aaaa aaab aaac aaba aabb aabc aaby aaca aacb aacc aacu aacy abaa abab abac abau abay abb- abba abbb abby abca abcb abcc abua abuy abyc abyy acaa acab acac acba acca accc accu accy acu- auaa auby auca ayay ayca ayub ayya baaa baba babb babu baby bac- baca bacc bau- baya bayu bbau bbay bbbb bcaa bcbc bcca bccc bcuc buba bubb bubu buca bucc bucu buyu caaa caab caac caba cabu caby cac- caca cacc cauc cbac cbbc cbca cbcc cbcu ccaa ccab ccac ccba ccbc ccca cccb cccc cccu ccuc cuau cub- cuba cubb cuby cuca cucc cuy- cya- cyaa cyba cybb cybc cyc- cyca cycb cycc cyy- cyyc uabc uaca uaua ubac ubay ubba ucbc ucca ucua uuuu yaba yacc yacy yaya yayu ycab yccc yuba yubu yuca yuya yuyu yyyy