aaaa aaab aaac aaar aaba aabb aabc aaca aacb aacc aaco aacr aaoo aara aarc aaro abaa abab abac abar abb- abba abbb abbo abbr abca abcb abcc abcr aboa abob aboo abor abra abrc abro acaa acab acac acar acba acca accc acco acoa acor acr- acra acrc acro acrr aoba aoca aora aorb arab arac arar arba arc- arca arco aroa arob aroo aror arr- arra arrc arro arrr baaa baar baba babb babo babr bac- baca bacc baco bar- bara barb barc baro barr bbbb bbrc bcaa bcar bcbc bcca bccc bcor bcra boab boac boar boba bobb bobo boca boco boob booc boor bor- bora boro borr brab brac brao brca brcb broa brob broc broo bror brrr c-bo caaa caab caac caba cabo cac- caca cacc caco cacr caor cara carb carc caro carr cbac cbar cbbc cbca cbcc cbcr ccaa ccab ccac ccar ccba ccbc ccca cccb cccc ccob ccoc ccra ccrc coba cobb cobo coca coco coob cor- cora corb corc coro corr crab crac crar crbc crca crcc crcr crob croc croo cror oara obba obbo obor obra obro ocab ocac ocbc occa occc ocra ocro ocrr ooaa ooba oocr oooo oora orab orac orao orar orba orbb orbo orca orco oro- oror orra orro raab raba rabb rabo rac- raca racc raco raob raoc rara rarb raro rbbb rbbr rcac rcbc rcbo rccb rccc roab roar rob- roba robb robo roca rocc roco roob roor rora rorc roro rrrr