a-ak a-be aaaa aaab aaac aaae aaar aaba aabb aabc aaca aacb aacc aace aack aacr aaea aaec aaka aake aara aarc aare abaa abab abac abae abak abar abb- abba abbb abbe abbr abca abcb abcc abcr abec abee aber abra abrc acaa acab acac acae acar acba acca accc acce ace- acea acec acek acer acke acr- acra acrc acre acrr aeac aecb aeer aeka aer- aera aerc akaa akae akar akca akee aker akka akr- akra akre arab arac arae arak arar arba arbe arc- arca arce area arec aree arek arka arke arr- arra arrc arre arrk arrr baaa baak baar baba babb babe babr bac- baca bacc bace back baek baer bak- baka bake bakr bar- bara barb barc bare bark barr bbbb bbeb bbrc bcaa bcar bcbc bcca bccc bcec bcer bcra beak bear beba bebb bebe beca beck beeb beek beer beka beke bera berc bere berk berr brab brac brae brak brca brcb brce brea breb brec bree brek brer brka brkb brrr caaa caab caac caba cabe cac- caca cacc cace cack cacr caec caer caka cake cara carb carc care cark carr cbac cbar cbbc cbca cbcc cbce cbcr cbea cbec cbee cber cbka cbkr cbre ccaa ccab ccac ccar ccba ccbc ccca cccb cccc ccee ccra ccrc ccre ceac cear ceba cec- ceca cece ceeb ceec ceke cer- cera cerc cere ckac ckbc ckbe ckck cker ckrc crab crac crar crbc crca crcc crce crcr cre- crea creb crec cree crkc eaba eaca eacc eaec eara earb eare ebac ebba ebbc ebbr ebcc eber ecaa ecac ecar ecbc ecbe ecca eccb eccc ecce ecka ecra ecrc ecrr eeca eeea eeee eeka eeke eera eerc eka- ekab ekeb ekek eker ekka erba erbb erbe erca ercc erce ereb erec erer erke erra errc erre kaaa kaab kaak kaar kaba kabb kabc kabe kabr kacb kacc kace kaer kaka kakc kake kakk kara karb kare kark karr kbaa kbab kbac kbae kbak kbar kbba kbbb kbbc kbbe kbbk kbbr kbca kbcb kbce kbck kbcr kbeb kbec kbee kbek kber kbkb kbkk kbkr kbra kbrb kbrc kbre kbrk kcaa kcab kcac kcar kcba kcbc kcbk kcbr kcca kccb kccc kcck kccr kcea kceb kcec kcee kckc kckk kckr kcrc kcrr kea- keak kear keba kebb kebc kebe kebr keca keck kecr keek keer keka kekb kekc keke ker- kera kerb kerc kere kerk kerr kkaa kkac kkar kkba kkbb kkbe kkbr kkcb kkck kkcr kkea kkkk kkrb kkrc kkre kkrk kkrr krab krac krae krak krar krba krbb krbe krbk krbr krca krcb krcc krce krea kreb krec kree krek krka krkc krke krkk krkr krrb krrc krre krrk krrr raab raak raba rabb rabe rabk rac- raca racc race rack raec raer raka rake rakk rara rarb rare rark rbbb rbbr rcac rcbc rccb rccc rea- reac reae reak rear reba rebb rebe rebk reca recc rece reck recr reeb reek reka reke rera rere rrrr