a-ak aaaa aaac aaaf aaca aacc aacf aack aafa aafc aaff aaka acaa acac acca accc accf acfc afaa afak afca afcc affa affc afka akaa akca akka caaa caac caaf cac- caca cacc cack cafa cafc caff caka ccaa ccac ccaf ccca cccc cccf ccfa ccfc ccff cfaa cfac cfca cfcf ckac ckck f--k faaa faac faca facc fack fafa fafc faff fcca fccf ffcc ffff kaaa kaaf kaak kacc kafa kafc kaff kaka kakc kakk kcaa kcac kcca kccc kcck kcfc kckc kckf kckk kfac kfcf kffa kfff kffk kfka kkaa kkac kkck kkkk