a-ya aaaa aaab aaac aaba aabb aabc aaby aaca aacb aacc aacy abaa abab abac abag abay abb- abba abbb abby abca abcb abcc abyc abyy acaa acab acac acag acba acca accc accy acga agac agag agay agba agca agcc agcy agga aggy agya ayay ayca ayya baaa baba babb baby bac- baca bacc baga bagg bagy baya bayg bbay bbbb bbga bcaa bcbc bcbg bcca bccc bgca bygg caaa caab caac caba cabg caby cac- caca cacc caga cagg cagy cbac cbbc cbca cbcc cbga cbgb ccaa ccab ccac ccag ccba ccbc ccca cccb cccc ccga ccgc cgac cgcc cgcg cya- cyaa cyba cybb cybc cyc- cyca cycb cycc cygb cyy- cyyc gaba gabb gaby gacy gaga gagg gaya gbag gc-c gcaa gcbc gccc gggg yaba yacc yacy yaga yaya ycab yccc yyyy