-ana a-ak aaaa aaab aaac aaan aaba aabb aabc aaca aacb aacc aack aacn aaka aana abaa abab abac abak aban abb- abba abbb abca abcb abcc abcn acaa acab acac acan acba acca accc akaa akan akca akka akna ana- anaa anab anac anak anan anba anbb anca ancc ank- anka anna annb baaa baak baan baba babb bac- baca bacc back bacn bak- baka bana banc bank bann bbbb bcaa bcbc bcca bccc caaa caab caac caan caba cac- caca cacc cack caka cana canc cank cann cbac cbbc cbca cbcc cbcn cbka cbkn cbna ccaa ccab ccac ccba ccbc ccbn ccca cccb cccc ccna ccnb ccnc ckac ckan ckbc ckck cknb cknc cnaa cnac cnbc cnna kaaa kaab kaak kaan kaba kabb kabc kacb kacc kaka kakc kakk kakn kana kanb kann kbaa kbab kbac kbak kbba kbbb kbbc kbbk kbca kbcb kbck kbkb kbkk kbna kbnn kcaa kcab kcac kcba kcbc kcbk kcca kccb kccc kcck kckc kckk kckn kcnb kkaa kkac kkan kkba kkbb kkbn kkcb kkck kkcn kkkk kknb kknn knaa knab knac knan knba knbb knbc knbn knca kncb knck kncn knkk knnb knnk naaa naab naac naan naba nabc nabk naca nacc nack naka nan- nana nanb nann nbaa nbak nbbc nbca nbcc ncaa ncac ncba ncbc ncca nccc nccn ncna ncnc nnnn