a-a a-b a-z aaa aab aad aae aaf aau aaz ab- aba abb abd abe abf abu abz ad- ada adb add ade adf adu adz aea aeb aed aee aef aeu aez af- afa afb afd afe aff afu afz au- aua aub aud aue auf auz az- aza azb azd aze azf azu azz b-u baa bab bad bae baf bau baz bba bbb bbd bbe bbf bbu bda bdb bdd bde bdf bdu bdz be- bea beb bed bee bef beu bez bfa bfb bfd bfe bff bfu bfz bua bub bud bue buf buu buz bza bzd bze bzf bzu bzz daa dab dad dae daf dau daz dba dbb dbd dbe dbf dbu dbz dda ddb ddd dde ddf ddu ddz de- dea deb ded dee def deu dez dfa dfb dfd dfe dff dfu dfz dua dub dud due duf duz dza dzb dzd dze dzu eaa eab ead eae eaf eau eaz eba ebb ebd ebe ebf ebu ed- eda edb edd ede edf edu eea eeb eed eee eef ef- efa efb efd efe eff eu- eua eub eud eue euf eze ezf ezz faa fab fad fae faf fau faz fba fbb fbd fbe fbf fbu fda fdb fdd fde fdf fdu fea feb fed fee fef feu fez ffa ffd ffe fff ffu ffz fua fub fud fue fuf fuu fzd ua- uaa uab uad uae uaf uau uaz uba ubb ube ubf ubu uda udb udd ude udf udu uea ueb ued uee uef ufa ufd ufe uff ufu uua uue uuu uza uzb uzu zaa zab zad zaf zaz zbb zdf zea zeb zed zee zef zez zfa zfd zub zud zuz zzz