a-wa aaaa aaab aaac aaba aabb aabc aabw aaca aacb aacc aaww abaa abab abac abaw abb- abba abbb abca abcb abcc abcw abwa acaa acab acac acba acca accc acwa acww awac awwa baaa baba babb bac- baca bacc baw- bbbb bbwc bcaa bcbc bcca bccc bwaa caaa caab caac caba cac- caca cacc cacw cbac cbbc cbca cbcc cbwa ccaa ccab ccac ccba ccbc ccca cccb cccc cwac waaa waac waaw waba wabb wabc wabw waca wacb wacc wawa wawb wawc wbaa wbab wbac wbbb wbbw wbca wbcb wbcw wbwb wbwc wcab wcba wcbc wcbw wcca wccb wccc wccw wcwa wcwb wcwc wwab wwac wwba wwbb wwbc wwca wwcb wwcw wwwa wwwc wwww