a-a a-b a-i aaa aab aae aag aai ab- aba abb abe abg abi aea aeb aee aeg aei ag- aga agb age agg agi ai- aia aib aie aig aii baa bab bae bag bai bba bbb bbe bbg bbi be- bea beb bee beg bei bga bgb bge bgg bgi bi- bia bib bie big bii eaa eab eae eag eai eba ebb ebe ebg ebi eea eeb eee eeg ega egb ege egg egi eia eib eie eig eii gaa gab gae gag gai gba gbe gbg gbi ge- gea geb gee geg gei gga ggb ggg ggi gia gib gie gig gii ia- iaa iab iae iag iai iba ibb ibe ibg ibi ie- iea iee ieg iei iga igb ige igg igi iia iib iie iii