a-ak aaaa aaab aaac aaaf aaas aaba aabb aabc aaca aacb aacc aacf aack aacs aafa aafb aafc aaff aaka aasa aasc aasf aass abaa abab abac abaf abak abas abax abb- abba abbb abbs abca abcb abcc abcf abcs abff abs- absa absf abss acaa acab acac acas acba acca accc accf accs acfc acfs acks acsa acsc acss afaa afak afbs afca afcb afcc afcs affa affc affs afka afsa afsb afsc akaa akas akca akka aksa asaa asab asac asaf asak asas asba asc- asca ascb ascc ascx asfa aska asks assa assc assk asss axaf axfs ba-x baaa baaf baak baas baba babb babs bac- baca bacc back bacs bafc baff bak- baka baks basa basc basf bask bass bbas bbbb bbbs bbfc bcaa bcas bcbc bcbs bcca bccc bccs bcfc bcsa bcsc bcss bfas bfca bfcs bffs bsaa bsac bsas bscs bsfa bsfc bsff bsfs bssc caaa caab caac caaf caas caba cabf cabs cac- caca cacc cack cafa cafb cafc caff cafs caka casa casb casc cask cass caxa cbac cbax cbbc cbbs cbca cbcc cbcs cbfb cbfc cbka cbsa cbsc cbxa ccaa ccab ccac ccaf ccas ccba ccbc ccca cccb cccc cccf cccs ccfa ccfc ccff ccsa ccsf ccss cfaa cfab cfac cfax cfbc cfbs cfca cfcb cfcf cfcs cffb cfsa cfsx ckac ckbc ckbx ckck ckcs ckcx cksa cksb csaa csab csac csak csas csbf cscb cscc cscf cscs csfc cska csks cssa cxfs cxxx f--k faaa faac faas faba fabs faca facc fack facs fafa fafc faff fasa fasc fass fcab fcas fcba fcbs fcca fccf fcsc ffcc ffff ffsa ffss fkab fsas fscb fscc fsck fssa fssc fssf kaaa kaab kaaf kaak kaas kaba kabb kabc kabf kacb kacc kacs kafa kafc kaff kafs kaka kakc kakk kaks kakx kas- kasa kasb kasc kasf kask kass kasx kaxa kbaa kbab kbac kbak kbas kbba kbbb kbbc kbbf kbbk kbbs kbca kbcb kbck kbcs kbfb kbfc kbff kbfk kbfs kbfx kbkb kbkf kbkk kbsa kbsb kbsk kbss kbsx kbxb kbxs kbxx kc-x kcaa kcab kcac kcas kcba kcbc kcbf kcbk kcbs kcbx kcca kccb kccc kcck kcfa kcfb kcfc kcfx kckc kckf kckk kckx kcsa kcsb kcsc kcsf kcss kfab kfac kfax kfbc kfbk kfbx kfcf kfcs kffa kffb kfff kffk kffx kfka kfkb kfkx kfsa kfsk kfxa kfxf kfxs kfxx kkaa kkac kkba kkbb kkbs kkcb kkck kkcs kkfs kkkk kksa kksf kkss kkxa kkxk kkxs kkxx ksab ksac ksaf ksak ksas ksba ksbc ksbs ksca kscb ksck kscs ksfa ksfb ksfc ksfx kska kskb kskf kskk ksks kskx kssa ksss kssx kxaa kxac kxas kxba kxbx kxca kxcs kxfc kxff kxkc kxkk kxks kxkx kxsb kxsc kxss kxxf kxxk kxxx sa-c sa-x saab saac saaf saak saas saba sabb sabc sabs saca sacc sack sacs safa safb safc saff saka sakb sakk saks sasa sasc sasf sask sass saxa sbaa sbac sbas sbbs sbca sbcc sbcs sbfc sbsa scaa scab scac scaf scak scas scba sccc sccs scfa scfc sck- scsa scsc sfas sfax sfba sfbc sfca sfcc sfcs sffc sfss skab skac skaf skfc skss ssaa ssab ssac ssas ssca sscc sscs ssfc sssa sssb sssc sssf ssss xcas xxxx