a-a a-b a-z aaa aab aad aae aaf aaz ab- aba abb abd abe abf abz ad- ada adb add ade adf adz aea aeb aed aee aef aez af- afa afb afd afe aff afz az- aza azb azd aze azf azz baa bab bad bae baf baz bba bbb bbd bbe bbf bda bdb bdd bde bdf bdz be- bea beb bed bee bef bez bfa bfb bfd bfe bff bfz bza bzd bze bzf bzz daa dab dad dae daf daz dba dbb dbd dbe dbf dbz dda ddb ddd dde ddf ddz de- dea deb ded dee def dez dfa dfb dfd dfe dff dfz dza dzb dzd dze eaa eab ead eae eaf eaz eba ebb ebd ebe ebf ed- eda edb edd ede edf eea eeb eed eee eef ef- efa efb efd efe eff eze ezf ezz faa fab fad fae faf faz fba fbb fbd fbe fbf fda fdb fdd fde fdf fea feb fed fee fef fez ffa ffd ffe fff ffz fzd zaa zab zad zaf zaz zbb zdf zea zeb zed zee zef zez zfa zfd zzz