-er a-a a-b a-i a-t aaa aab aae aai aar aat aav aax ab- aba abb abe abi abr abt abv abx aea aeb aee aei aer aet aev aex ai- aia aib aie aii air ait aiv aix ar- ara arb are ari arr art arv arx at- ata atb ate ati atr att atv atx av- ava avb ave avi avr avt avx ax- axa axe axi axr axt axv axx baa bab bae bai bar bat bav bax bba bbb bbe bbi bbr bbt bbx be- bea beb bee bei ber bet bev bex bi- bia bib bie bii bir bit biv bix bra brb bre bri brr brt brv brx bta btb bte bti btr btt btv btx bva bvb bve bvi bvr bvt bvv bxb bxi bxx eaa eab eae eai ear eat eav eax eba ebb ebe ebi ebr ebt ebv ebx eea eeb eee eer eet eev eex eia eib eie eii eir eit eiv eix era erb ere eri err ert erv eta etb ete eti etr ett etv etx eva evb eve evi evr evt evv ex- exa exe exi exr ext exx i-v ia- iaa iab iae iai iar iat iav iba ibb ibe ibi ibr ibt ibv ibx ie- iea iee iei ier iet iev iex iia iib iie iii iir iit iix ir- ira irb ire iri irr irt irv irx ita itb ite iti itt itv itx iva ivb ive ivi ivr ivt ivv ivx ixe ixi ra- raa rab rae rai rar rat rav rax rba rbb rbe rbi rbr rbt rbx re- rea reb ree rei rer ret rev rex ria rib rie rii rir rit riv rix rra rrb rri rrr rrt rta rtb rte rti rtr rtt rtv rtx rva rvb rve rvi rvr rvt rvv rxr t-x taa tab tae tai tar tat tav tax tba tbb tbe tbi tbr tbt tbv te- tea teb tee tei ter tet tev tex tia tib tie tii tir tit tiv tix tra trb tre tri trr trt trv trx tta ttb tte tti ttr ttt ttv ttx tva tvb tve tvi tvr tvt tvx txe txi txt v-a v-e vaa vab vae vai var vat vav vax vba vbi vbr vbv vea veb vee vei ver vet vex vi- via vib vie vii vir vit viv vix vra vrb vre vri vrr vrt vta vtb vte vti vtr vtt vtv vtx vva vvb vvi vvr vvt vvv vxa vxr vxv xaa xar xat xav xbe xbr xbx xee xer xet xev xex xia xie xii xit xiv xix xrt xrx xti xtr xtv xtx xvi xvt xxi xxv xxx