-er a-a a-b a-i a-t aaa aab aae aai aan aar aat ab- aba abb abe abi abn abr abt aea aeb aee aei aen aer aet ai- aia aib aie aii ain air ait an- ana anb ane ani ann anr ant ar- ara arb are ari arn arr art at- ata atb ate ati atn atr att baa bab bae bai ban bar bat bba bbb bbe bbi bbn bbr bbt be- bea beb bee bei ben ber bet bi- bia bib bie bii bin bir bit bna bnb bne bni bnn bnr bnt bra brb bre bri brn brr brt bta btb bte bti btn btr btt eaa eab eae eai ean ear eat eba ebb ebe ebi ebn ebr ebt eea eeb eee een eer eet eia eib eie eii ein eir eit en- ena enb ene eni enn enr ent era erb ere eri ern err ert eta etb ete eti etn etr ett ia- iaa iab iae iai ian iar iat iba ibb ibe ibi ibn ibr ibt ie- iea iee iei ien ier iet iia iib iie iii iin iir iit in- ina inb ine ini inn inr int ir- ira irb ire iri irn irr irt ita itb ite iti itn itt n-i naa nab nae nai nan nar nat nba nbb nbe nbi nbn nbr nbt ne- nea neb nee nei nen ner net nia nib nie nii nin nir nit nna nnb nne nni nnn nnt nra nrb nre nri nrn nrr nrt nta ntb nte nti ntn ntr ntt ra- raa rab rae rai ran rar rat rba rbb rbe rbi rbn rbr rbt re- rea reb ree rei ren rer ret ria rib rie rii rin rir rit rna rnb rni rnn rnr rnt rra rrb rri rrn rrr rrt rta rtb rte rti rtn rtr rtt taa tab tae tai tan tar tat tba tbb tbe tbi tbn tbr tbt te- tea teb tee tei ten ter tet tia tib tie tii tin tir tit tna tnb tne tni tnn tnr tnt tra trb tre tri trn trr trt tta ttb tte tti ttn ttr ttt