aaaa aaab aaac aaar aaba aabb aabc aaca aacb aacc aacr aara aarc abaa abab abac abar abb- abba abbb abbr abca abcb abcc abcr abra abrc acaa acab acac acar acba acca accc acr- acra acrc acrr arab arac arar arba arc- arca arr- arra arrc arrr baaa baar baba babb babr bac- baca bacc bar- bara barb barc barr bbbb bbrc bcaa bcar bcbc bcca bccc bcra brab brac brca brcb brrr caaa caab caac caba cac- caca cacc cacr cara carb carc carr cbac cbar cbbc cbca cbcc cbcr ccaa ccab ccac ccar ccba ccbc ccca cccb cccc ccra ccrc crab crac crar crbc crca crcc crcr raab raba rabb rac- raca racc rara rarb rbbb rbbr rcac rcbc rccb rccc rrrr