aaaa aaab aaac aaal aaba aabb aabc aabl aaca aacb aacc aacl aala aalc aall abaa abab abac abal abb- abba abbb abca abcb abcc abcl abla acaa acab acac acba acbl acca accc acla aclc alaa alac alal alb- alba albc alca alcc all- alla alll baaa baal baba babb bac- baca bacc bala balc ball bbbb bblb bcaa bcbc bcca bccc bccl blaa blab blac caaa caab caac caal caba cac- caca cacc cala calc call cbac cbal cbbc cbca cbcc cbcl cblb cblc ccaa ccab ccac ccba ccbc ccca cccb cccc cccl ccla cclc clab laaa laac laal laba laca lacc lacl lala lall lbcc lcac lcbc lcca lccc llcc lllc llll