a-ak aaaa aaab aaac aaar aaas aaba aabb aabc aaca aacb aacc aack aacr aacs aaka aara aarc aars aasa aasc aass abaa abab abac abak abar abas abb- abba abbb abbr abbs abca abcb abcc abcr abcs abra abrc abrs abs- absa abss acaa acab acac acar acas acba acca accc accs acks acr- acra acrc acrr acrs acsa acsc acss akaa akar akas akca akka akr- akra aksa arab arac arak arar aras arba arbs arc- arca arcs arka arks arr- arra arrc arrk arrr arrs ars- arsa arsc arsk asaa asab asac asak asar asas asba asc- asca ascb ascc ascr aska askr asks asra asrc asrs assa assc assk assr asss baaa baak baar baas baba babb babr babs bac- baca bacc back bacs bak- baka bakr baks bar- bara barb barc bark barr bars basa basc bask bass bbas bbbb bbbs bbrc bcaa bcar bcas bcbc bcbs bcca bccc bccs bcra bcrs bcsa bcsc bcss brab brac brak bras brca brcb brka brkb brrr brrs brsb brsr bsaa bsac bsas bscs bsra bssc caaa caab caac caas caba cabs cac- caca cacc cack cacr caka cara carb carc cark carr cars casa casb casc cask casr cass cbac cbar cbbc cbbs cbca cbcc cbcr cbcs cbka cbkr cbsa cbsc ccaa ccab ccac ccar ccas ccba ccbc ccca cccb cccc cccs ccra ccrc ccrs ccsa ccss ckac ckbc ckck ckcs ckrc cksa cksb crab crac crar cras crbc crca crcc crcr crkc crsa crss csaa csab csac csak csar csas cscb cscc cscr cscs cska csks csra csrc csrs cssa cssr kaaa kaab kaak kaar kaas kaba kabb kabc kabr kacb kacc kacs kaka kakc kakk kaks kara karb kark karr kars kas- kasa kasb kasc kask kasr kass kbaa kbab kbac kbak kbar kbas kbba kbbb kbbc kbbk kbbr kbbs kbca kbcb kbck kbcr kbcs kbkb kbkk kbkr kbra kbrb kbrc kbrk kbsa kbsb kbsk kbsr kbss kcaa kcab kcac kcar kcas kcba kcbc kcbk kcbr kcbs kcca kccb kccc kcck kccr kckc kckk kckr kcrc kcrr kcrs kcsa kcsb kcsc kcsr kcss kkaa kkac kkar kkba kkbb kkbr kkbs kkcb kkck kkcr kkcs kkkk kkrb kkrc kkrk kkrr kkrs kksa kksr kkss krab krac krak krar kras krba krbb krbk krbr krca krcb krcc krcs krka krkc krkk krkr krks krrb krrc krrk krrr krrs krsa krsc krsk krsr krss ksab ksac ksak ksar ksas ksba ksbc ksbr ksbs ksca kscb ksck kscr kscs kska kskb kskk kskr ksks ksra ksrb ksrr ksrs kssa kssr ksss raab raak raas raba rabb rabk rabs rac- raca racc rack racs raka rakk rara rarb rark rars rasa rasc rask rass rbbb rbbr rbbs rbss rcac rcas rcbc rccb rccc rccs rcsa rcsc rcss rkss rras rrrr rsaa rscc rscs rssa sa-c saab saac saak saar saas saba sabb sabc sabr sabs saca sacc sack sacr sacs saka sakb sakk saks sara sarc sark sarr sars sasa sasc sask sass sbaa sbac sbar sbas sbbs sbca sbcc sbcs sbrk sbsa scaa scab scac scak scar scas scba sccc sccs sck- scr- scra scrc scrs scsa scsc scsr skab skac skar skra skss sras srbc srcc ssaa ssab ssac ssas ssbr ssca sscc sscs ssra ssrc ssrs sssa sssb sssc ssss