a-ak aaaa aaab aaac aaba aabb aabc aaca aacb aacc aack aaka abaa abab abac abaj abak abb- abba abbb abca abcb abcc acaa acab acac acba acca accc ajab ajac ajak ajba ajka akaa akca akka baaa baak baba babb bac- baca bacc back baja bak- baka bbbb bcaa bcbc bcca bccc bjcc caaa caab caac caba cac- caca cacc cack caja caka cbac cbbc cbca cbcc cbka cbkj ccaa ccab ccac ccba ccbc ccca cccb cccc cjbc cjbk cjca cjcb cjcj ckac ckbc ckck jaak jaba jaca jacc jack jaja jaka jbaa jcbc jccc jjcc kaaa kaab kaak kaba kabb kabc kacb kacc kaja kajb kajc kajk kaka kakc kakj kakk kbaa kbab kbac kbak kbba kbbb kbbc kbbk kbca kbcb kbck kbja kbjc kbjk kbkb kbkk kcaa kcab kcac kcba kcbc kcbk kcca kccb kccc kcck kcjb kcjc kcjj kcjk kckc kckj kckk kjaa kjac kjak kjbb kjcb kjcc kjck kjjj kjjk kjkj kjkk kkaa kkac kkba kkbb kkbj kkcb kkcj kkck kkjb kkjk kkkj kkkk