a-ak aaaa aaac aaaf aaas aaca aacc aacf aack aacs aafa aafc aaff aaka aasa aasc aasf aass acaa acac acas acca accc accf accs acfc acfs acks acsa acsc acss afaa afak afca afcc afcs affa affc affs afka afsa afsc akaa akas akca akka aksa asaa asac asaf asak asas asc- asca ascc asfa aska asks assa assc assk asss caaa caac caaf caas cac- caca cacc cack cafa cafc caff cafs caka casa casc cask cass ccaa ccac ccaf ccas ccca cccc cccf cccs ccfa ccfc ccff ccsa ccsf ccss cfaa cfac cfca cfcf cfcs cfsa ckac ckck ckcs cksa csaa csac csak csas cscc cscf cscs csfc cska csks cssa f--k faaa faac faas faca facc fack facs fafa fafc faff fasa fasc fass fcas fcca fccf fcsc ffcc ffff ffsa ffss fsas fscc fsck fssa fssc fssf kaaa kaaf kaak kaas kacc kacs kafa kafc kaff kafs kaka kakc kakk kaks kas- kasa kasc kasf kask kass kcaa kcac kcas kcca kccc kcck kcfa kcfc kckc kckf kckk kcsa kcsc kcsf kcss kfac kfcf kfcs kffa kfff kffk kfka kfsa kfsk kkaa kkac kkck kkcs kkfs kkkk kksa kksf kkss ksac ksaf ksak ksas ksca ksck kscs ksfa ksfc kska kskf kskk ksks kssa ksss sa-c saac saaf saak saas saca sacc sack sacs safa safc saff saka sakk saks sasa sasc sasf sask sass scaa scac scaf scak scas sccc sccs scfa scfc sck- scsa scsc sfas sfca sfcc sfcs sffc sfss skac skaf skfc skss ssaa ssac ssas ssca sscc sscs ssfc sssa sssc sssf ssss