a-a a-b a-i aaa aab aag aai aan aar aax ab- aba abb abg abi abn abr abx ag- aga agb agg agi agn agr agx ai- aia aib aig aii ain air aix an- ana anb ang ani ann anr anx ar- ara arb arg ari arn arr arx ax- axa axi axn axr axx baa bab bag bai ban bar bax bba bbb bbg bbi bbn bbr bbx bga bgb bgg bgi bgn bgr bgx bi- bia bib big bii bin bir bix bna bnb bng bni bnn bnr bnx bra brb brg bri brn brr brx bxb bxi bxn bxx gaa gab gag gai gan gar gba gbg gbi gbn gbr gbx gga ggb ggg ggi ggn ggr gia gib gig gii gin gir gna gnb gni gnn gnr gra grb grg gri grn grr grx gxa ia- iaa iab iag iai ian iar iba ibb ibg ibi ibn ibr ibx iga igb igg igi ign igr iia iib iii iin iir iix in- ina inb ing ini inn inr inx ir- ira irb irg iri irn irr irx ixi ixn n-i naa nab nag nai nan nar nax nba nbb nbg nbi nbn nbr nbx nga ngb ngg ngi ngn nia nib nig nii nin nir nix nna nnb nng nni nnn nra nrb nrg nri nrn nrr nrx ra- raa rab rag rai ran rar rax rba rbb rbg rbi rbn rbr rbx rga rgb rgg rgi rgn rgr rgx ria rib rig rii rin rir rix rna rnb rng rni rnn rnr rra rrb rrg rri rrn rrr rxr xaa xag xan xar xbr xbx xgi xia xii xin xix xna xrx xxi xxx