a-a a-b a-z aaa aab aae aag aaz ab- aba abb abe abg abz aea aeb aee aeg aez ag- aga agb age agg agz az- aza azb aze azg azz baa bab bae bag baz bba bbb bbe bbg be- bea beb bee beg bez bga bgb bge bgg bgz bza bze bzz eaa eab eae eag eaz eba ebb ebe ebg eea eeb eee eeg ega egb ege egg eze ezz gaa gab gae gag gaz gba gbe gbg gbz ge- gea geb gee geg gez gga ggb ggg ggz gza z-g zaa zab zag zaz zbb zea zeb zee zez zgb zgg zzz