a-a a-b a-i a-t aaa aab aaf aag aai aao aar aat ab- aba abb abf abg abi abo abr abt af- afa afb aff afg afi afo afr aft ag- aga agb agf agg agi ago agr agt ai- aia aib aif aig aii aio air ait aoa aob aof aog aoi aoo aor aot ar- ara arb arf arg ari aro arr art at- ata atb atf atg ati ato atr att baa bab baf bag bai bao bar bat bba bbb bbf bbg bbi bbo bbr bbt bfa bfb bff bfg bfi bfo bfr bft bga bgb bgf bgg bgi bgo bgr bgt bi- bia bib bif big bii bio bir bit boa bob bof bog boi boo bor bot bra brb brf brg bri bro brr brt bta btb btf btg bti bto btr btt faa fab faf fag fai fao far fat fba fbb fbf fbg fbi fbo fbr fbt ffa fff ffg ffi ffo ffr fft fga fgb fgf fgg fgi fgr fgt fia fib fif fig fii fir fit foa fob fof fog foi foo for fot fra frb frf frg fri fro frr frt fta ftb ftf ftg fti fto ftr ftt gaa gab gaf gag gai gao gar gat gba gbf gbg gbi gbo gbr gbt gfa gfb gff gfi gfo gfr gft gga ggb ggg ggi ggo ggr ggt gia gib gif gig gii gio gir git goa gob gof gog goi goo gor got gra grb grf grg gri gro grr grt gta gtb gtf gtg gti gto gtr gtt i-f ia- iaa iab iaf iag iai iao iar iat iba ibb ibf ibg ibi ibo ibr ibt ifa ifb iff ifg ifi ifo ifr ift iga igb igf igg igi igo igr igt iia iib iif iii iio iir iit io- ioa iob iof iog ioi ioo ior iot ir- ira irb irf irg iri iro irr irt ita itb itf itg iti ito itt o-i oaa oab oaf oag oai oao oar oat ob- oba obb obf obg obi obo obr obt of- ofa ofb off ofg ofi ofo ofr oft oga ogf ogg ogi ogo ogt oia oib oif oii oio oir oit oo- ooa oob oof oog ooi ooo oor oot or- ora orb orf org ori oro orr ort ot- ota otb otf otg oti oto otr ott ra- raa rab raf rag rai rao rar rat rba rbb rbf rbg rbi rbo rbr rbt rfa rfb rff rfg rfi rfo rfr rft rga rgb rgf rgg rgi rgo rgr rgt ria rib rif rig rii rio rir rit roa rob rof rog roi roo ror rot rra rrb rrf rrg rri rrr rrt rta rtb rtf rtg rti rto rtr rtt taa tab taf tag tai tao tar tat tba tbb tbf tbg tbi tbo tbr tbt tfa tfb tff tfg tfi tfo tfr tft tga tgb tgf tgg tgi tgo tgr tgt tia tib tif tig tii tio tir tit to- toa tob tof tog toi too tor tot tra trb trf trg tri tro trr trt tta ttb ttf ttg tti tto ttr ttt