a-a a-b a-i a-t aaa aab aag aai aao aar aat ab- aba abb abg abi abo abr abt ag- aga agb agg agi ago agr agt ai- aia aib aig aii aio air ait aoa aob aog aoi aoo aor aot ar- ara arb arg ari aro arr art at- ata atb atg ati ato atr att baa bab bag bai bao bar bat bba bbb bbg bbi bbo bbr bbt bga bgb bgg bgi bgo bgr bgt bi- bia bib big bii bio bir bit boa bob bog boi boo bor bot bra brb brg bri bro brr brt bta btb btg bti bto btr btt gaa gab gag gai gao gar gat gba gbg gbi gbo gbr gbt gga ggb ggg ggi ggo ggr ggt gia gib gig gii gio gir git goa gob gog goi goo gor got gra grb grg gri gro grr grt gta gtb gtg gti gto gtr gtt ia- iaa iab iag iai iao iar iat iba ibb ibg ibi ibo ibr ibt iga igb igg igi igo igr igt iia iib iii iio iir iit io- ioa iob iog ioi ioo ior iot ir- ira irb irg iri iro irr irt ita itb itg iti ito itt o-i oaa oab oag oai oao oar oat ob- oba obb obg obi obo obr obt oga ogg ogi ogo ogt oia oib oii oio oir oit oo- ooa oob oog ooi ooo oor oot or- ora orb org ori oro orr ort ot- ota otb otg oti oto otr ott ra- raa rab rag rai rao rar rat rba rbb rbg rbi rbo rbr rbt rga rgb rgg rgi rgo rgr rgt ria rib rig rii rio rir rit roa rob rog roi roo ror rot rra rrb rrg rri rrr rrt rta rtb rtg rti rto rtr rtt taa tab tag tai tao tar tat tba tbb tbg tbi tbo tbr tbt tga tgb tgg tgi tgo tgr tgt tia tib tig tii tio tir tit to- toa tob tog toi too tor tot tra trb trg tri tro trr trt tta ttb ttg tti tto ttr ttt