a-a a-b a-i aaa aab aag aai aao ab- aba abb abg abi abo ag- aga agb agg agi ago ai- aia aib aig aii aio aoa aob aog aoi aoo baa bab bag bai bao bba bbb bbg bbi bbo bga bgb bgg bgi bgo bi- bia bib big bii bio boa bob bog boi boo gaa gab gag gai gao gba gbg gbi gbo gga ggb ggg ggi ggo gia gib gig gii gio goa gob gog goi goo ia- iaa iab iag iai iao iba ibb ibg ibi ibo iga igb igg igi igo iia iib iii iio io- ioa iob iog ioi ioo o-i oaa oab oag oai oao ob- oba obb obg obi obo oga ogg ogi ogo oia oib oii oio oo- ooa oob oog ooi ooo