a-a a-b a-i a-t aaa aab aai aan aar aat ab- aba abb abi abn abr abt ai- aia aib aii ain air ait an- ana anb ani ann anr ant ar- ara arb ari arn arr art at- ata atb ati atn atr att baa bab bai ban bar bat bba bbb bbi bbn bbr bbt bi- bia bib bii bin bir bit bna bnb bni bnn bnr bnt bra brb bri brn brr brt bta btb bti btn btr btt ia- iaa iab iai ian iar iat iba ibb ibi ibn ibr ibt iia iib iii iin iir iit in- ina inb ini inn inr int ir- ira irb iri irn irr irt ita itb iti itn itt n-i naa nab nai nan nar nat nba nbb nbi nbn nbr nbt nia nib nii nin nir nit nna nnb nni nnn nnt nra nrb nri nrn nrr nrt nta ntb nti ntn ntr ntt ra- raa rab rai ran rar rat rba rbb rbi rbn rbr rbt ria rib rii rin rir rit rna rnb rni rnn rnr rnt rra rrb rri rrn rrr rrt rta rtb rti rtn rtr rtt taa tab tai tan tar tat tba tbb tbi tbn tbr tbt tia tib tii tin tir tit tna tnb tni tnn tnr tnt tra trb tri trn trr trt tta ttb tti ttn ttr ttt