a-ak aaaa aaab aaac aaal aaas aaba aabb aabc aabl aaca aacb aacc aack aacl aacs aaka aala aalc aall aals aasa aasc aass abaa abab abac abak abal abas abb- abba abbb abbs abca abcb abcc abcl abcs abla abls abs- absa absl abss acaa acab acac acas acba acbl acca accc accs acks acla aclc acls acsa acsc acsl acss akaa akal akas akca akka aksa alaa alac alak alal alas alb- alba albc albs alca alcc alcs alk- alka alkb all- alla alll alls alsa alsc asaa asab asac asak asal asas asba asc- asca ascb ascc ascl aska asks asla assa assc assk assl asss baaa baak baal baas baba babb babs bac- baca bacc back bacs bak- baka bakl baks bala balc balk ball bals basa basc bask bass bbas bbbb bbbs bblb bbls bcaa bcas bcbc bcbs bcca bccc bccl bccs bcsa bcsc bcsl bcss blaa blab blac blak blas blkb blls blss bsaa bsac bsas bscs bslc bssc caaa caab caac caal caas caba cabs cac- caca cacc cack caka cala calc calk call cals casa casb casc cask casl cass cbac cbal cbbc cbbs cbca cbcc cbcl cbcs cbka cbkl cblb cblc cbsa cbsc ccaa ccab ccac ccas ccba ccbc ccca cccb cccc cccl cccs ccla cclc ccls ccsa ccsl ccss ckac ckbc ckck ckcl ckcs cksa cksb cksl clab clas clsa clsc csaa csab csac csak csas cscb cscc cscl cscs cska csks csla cssa kaaa kaab kaak kaal kaas kaba kabb kabc kacb kacc kacl kacs kaka kakc kakk kaks kala kalb kalc kalk kall kals kas- kasa kasb kasc kask kasl kass kbaa kbab kbac kbak kbal kbas kbba kbbb kbbc kbbk kbbl kbbs kbca kbcb kbck kbcl kbcs kbkb kbkk kbkl kbla kblb kbll kbls kbsa kbsb kbsk kbss kcaa kcab kcac kcal kcas kcba kcbc kcbk kcbl kcbs kcca kccb kccc kcck kccl kckc kckk kckl kcla kclc kclk kcll kcls kcsa kcsb kcsc kcss kkaa kkac kkal kkba kkbb kkbl kkbs kkcb kkck kkcl kkcs kkkk kklb kklc kkll kkls kksa kkss klaa klab klac klak klal klas klbb klbc klbl klbs klca klcb klcc klck klcl klcs klka klkc klkk klkl klks klla kllb kllc kllk klls klsa klsc ksab ksac ksak ksal ksas ksba ksbc ksbl ksbs ksca kscb ksck kscl kscs kska kskb kskk ksks ksla kslb kslc kslk ksll kssa kssl ksss laaa laac laak laal laas laba labs laca lacc lack lacl lacs laka laks lala lall lasa lask lass lbcc lbsc lcac lcbc lcca lccc lccs lcls lcsc lkab lkal llbs llcc llcs llks lllc llll lscb lscs lsla lssa sa-c saab saac saak saal saas saba sabb sabc sabs saca sacc sack sacs saka sakb sakk saks sala salc salk sall sals sasa sasc sask sasl sass sbaa sbac sbas sbbs sbca sbcc sbcs sbsa scaa scab scac scak scal scas scba sccc sccl sccs sck- sckl scl- sclc sclk scls scsa scsc scsl skab skac skal skss slaa slab slac slak slas slcc slsa slsc ssaa ssab ssac ssas ssca sscc sscs ssla sslc sssa sssb sssc ssss