a-ak a-do a-ok aaaa aaab aaac aaad aaar aaba aabb aabc aabd aaca aacb aacc aacd aack aaco aacr aada aadc aaka aaoo aara aarc aard aaro abaa abab abac abad abak abar abb- abba abbb abbo abbr abca abcb abcc abcd abcr abda abdo aboa abob abod abok aboo abor abra abrc abro acaa acab acac acad acar acba acca accc accd acco acda acdb acdc ackd acoa acod acor acr- acra acrc acro acrr adaa adab adac adad adak adao adar adba adbc adcc adda addc addd addo addr adob adoc adod adok adoo ador adra adro akaa akao akar akca akka akko akok akr- akra aoba aoca aora aorb arab arac arad arak arar arba arc- arca arco arda ardc ardo arka arko aroa arob arod aroo aror arr- arra arrc arrk arro arrr baaa baad baak baar baba babb babo babr bac- baca bacc back baco bada badb badd bado badr bak- baka bako bakr bar- bara barb barc bard bark baro barr bbad bbbb bbdd bbdo bbrc bcaa bcar bcbc bcca bccc bcda bcor bcra bd-r bdbc bddc boab boac boad boak boar boba bobb bobo boca bock boco boda bodb bodo boka boko boob booc bood book boor bor- bora bord bork boro borr brab brac brad brak brao brca brcb brda brdo brka brkb broa brob broc brod brok broo bror brrr c-bo c-cd caaa caab caac caba cabo cac- caca cacc cack caco cacr cada cadc cadd cado cadr caka caod caor cara carb carc card cark caro carr cbac cbar cbbc cbca cbcc cbcr cbdb cbdc cbdo cbka cbko cbkr cbrd ccaa ccab ccac ccad ccar ccba ccbc ccca cccb cccc ccdc ccdr ccob ccoc ccod ccra ccrc cd-r cdaa cdac cdad cdba cdda cddb cddr ckac ckbc ckck ckco ckdo ckoa ckob ckoc ckoo ckor ckrc ckrd coad coak coba cobb cobo coca cock coco coda codd cok- coka coko coob cood cook cor- cora corb corc cord cork coro corr crab crac crar crbc crca crcc crcr crda crdc crkc crob croc crod crok croo cror d-bo daab daad daar daba dabb dabo daca dada dado daka dako dara darb darc dard dark daro darr dbar dbcc dcbc dcca dccb dccc dcdb dcra dcrk dddd ddoc ddrc dkba dkdc doab doak doar doba dobb doca dock doco dod- doda dodd dodo doka doko doob dood dook door dora dorc dord dork doro dorr draa drab drac drad drak drar drba drbc drca drda drob drod drra kaaa kaab kaak kaar kaba kabb kabc kabd kabo kabr kacb kacc kacd kaco kad- kada kadd kado kadr kaka kakc kakk kako kaoa kaoc kaok kaor kara karb kard kark karo karr kbaa kbab kbac kbad kbak kbar kbba kbbb kbbc kbbd kbbk kbbo kbbr kbca kbcb kbck kbco kbcr kbdb kbdo kbdr kbkb kbkk kbko kbkr kboa kbob kboc kbod kbok kboo kbra kbrb kbrc kbrd kbrk kbro kcaa kcab kcac kcad kcar kcba kcbc kcbd kcbk kcbr kcca kccb kccc kccd kcck kccr kcda kcdc kcdd kcdr kckc kckk kcko kckr kcob kcor kcrc kcro kcrr kdaa kdab kdac kdad kdak kdao kdar kdbb kdbr kdca kdcc kdcd kdco kdcr kddb kddc kddd kddk kddr kdka kdkb kdkd kdkk kdko kdkr kdoc kdok kdrb kdro kkaa kkac kkar kkba kkbb kkbd kkbo kkbr kkcb kkcd kkck kkco kkcr kkda kkdc kkdd kkdo kkkk kkoa kkob kkoo kkor kkrb kkrc kkrk kkro kkrr koab koac koak koar koba kobb kobc kobk kobo kobr koca kocb kocd kock koda kodk kodo koka kokb kokc kokk koko kokr koob kooc kook kooo koor kora korb korc kord kork koro korr krab krac krad krak krar krba krbb krbd krbk krbr krca krcb krcc krcd krco krda krdc krdd krdo krdr krka krkc krkd krkk krko krkr kroa krob kroc krod krok kroo kror krrb krrc krrk krro krrr oara obad obak obba obbo obkb obok obor obra obro ocab ocac ocad ocak ocbc occa occc ocra ocro ocrr odac odbo odda oddd odoo odor odra okak okka okko okok okor okra okro ooaa ooak ooba oocr ooda oooo oora oord orab orac orad orak orao orar orba orbb orbo orca orco orda ordo orka orko oro- orok oror orra orro raab raad raak raba rabb rabk rabo rac- raca racc rack raco rada radc radd rado radr raka rakk raob raoc raok rara rarb rark raro rbbb rbbr rcac rcbc rcbo rccb rccc rcdc rcrd rdac rdoc roab road roak roar rob- roba robb robo roca rocc rock roco roda rodd rodo roka rokk roko rokr roob rood rook roor rora rorc rork roro rrad rrrr