a-a a-b aaa aab aag aao aau ab- aba abb abg abo abu ag- aga agb agg ago agu aoa aob aog aoo aou au- aua aub aug auo b-u baa bab bag bao bau bba bbb bbg bbo bbu bga bgb bgg bgo bgu boa bob bog boo bou bua bub bug buo buu gaa gab gag gao gau gba gbg gbo gbu gga ggb ggg ggo ggu goa gob gog goo gou gu- gua gub gug guo guu oaa oab oag oao oau ob- oba obb obg obo obu oga ogg ogo oo- ooa oob oog ooo ou- oua ouo ua- uaa uab uag uao uau uba ubb ubg ubo ubu uga ugb ugg ugo ugu uoa uob uog uoo uua uug uuu