a-ak a-be a-ok aaaa aaab aaac aaae aaba aabb aabc aaca aacb aacc aace aack aaco aaea aaec aaka aake aaoe aaoo abaa abab abac abae abak abb- abba abbb abbe abbo abca abcb abcc abec abee aboa abob abok aboo acaa acab acac acae acba acca accc acce acco ace- acea acec acek acke acoa acoe aeac aecb aeka akaa akae akao akca akee akka akko akok aoba aoca aoce baaa baak baba babb babe babo bac- baca bacc bace back baco baek bak- baka bake bako bbbb bbeb bcaa bcbc bcca bccc bcec beak beba bebb bebe bebo beca beck beeb beek beka beke beko beo- beok boab boac boak boba bobb bobe bobo boca boce bock boco boea boec boee boeo boka boke boko boob booc booe book c-bo caaa caab caac caba cabe cabo cac- caca cacc cace cack caco caec caka cake cbac cbbc cbca cbcc cbce cbea cbec cbee cbka cbko ccaa ccab ccac ccba ccbc ccca cccb cccc ccee ccob ccoc ceac ceba cec- ceca cece ceco ceeb ceec ceke ckac ckbc ckbe ckck ckco ckoa ckob ckoc ckoo coak coba cobb cobe cobo coca coce cock coco cok- coka coke coko coob cook eaba eaca eacc eaec ebac ebba ebbc ebbo ebcc eboe eboo ecaa ecac ecao ecbc ecbe ecca eccb eccc ecce ecco ecka ecko eco- eeca eeea eeee eeka eeke eeoc eka- ekab ekco ekeb ekek ekka ekoa eoka kaaa kaab kaak kaba kabb kabc kabe kabo kacb kacc kace kaco kaeo kaka kakc kake kakk kako kaoa kaoc kaok kbaa kbab kbac kbae kbak kbba kbbb kbbc kbbe kbbk kbbo kbca kbcb kbce kbck kbco kbeb kbec kbee kbek kbeo kbkb kbkk kbko kboa kbob kboc kboe kbok kboo kcaa kcab kcac kcba kcbc kcbk kcca kccb kccc kcck kcea kceb kcec kcee kceo kckc kckk kcko kcob kcoe kea- keak keba kebb kebc kebe keca keck keco keek keka kekb kekc keke keko keok kkaa kkac kkba kkbb kkbe kkbo kkcb kkck kkco kkea kkkk kkoa kkob kkoo koab koac koae koak koba kobb kobc kobe kobk kobo koca kocb kock koea koka kokb kokc koke kokk koko koob kooc kook kooo o-eo oake obak obba obbo obea obec obkb oboe obok ocab ocac ocak ocbc occa occc oce ocee ocke oec- oeca oecc oeec okak okka okko okok ooaa ooak ooba oobe oooo