a-a a-b a-i a-t aaa aab aag aai aao aas aat ab- aba abb abg abi abo abs abt ag- aga agb agg agi ago ags agt ai- aia aib aig aii aio ais ait aoa aob aog aoi aoo aos aot as- asa asb asg asi aso ass ast at- ata atb atg ati ato ats att baa bab bag bai bao bas bat bba bbb bbg bbi bbo bbs bbt bga bgb bgg bgi bgo bgs bgt bi- bia bib big bii bio bis bit boa bob bog boi boo bos bot bsa bsb bsg bsi bso bss bst bta btb btg bti bto bts btt gaa gab gag gai gao gas gat gba gbg gbi gbo gbs gbt gga ggb ggg ggi ggo ggs ggt gia gib gig gii gio gis git goa gob gog goi goo gos got gsa gsb gsg gsi gso gss gst gta gtb gtg gti gto gts gtt ia- iaa iab iag iai iao ias iat iba ibb ibg ibi ibo ibs ibt iga igb igg igi igo igs igt iia iib iii iio iis iit io- ioa iob iog ioi ioo ios iot is- isa isb isg isi iso iss ist ita itb itg iti ito its itt o-i oaa oab oag oai oao oas oat ob- oba obb obg obi obo obs obt oga ogg ogi ogo ogs ogt oia oib oii oio ois oit oo- ooa oob oog ooi ooo oos oot os- osa osb osg osi oso oss ost ot- ota otb otg oti oto ots ott saa sab sag sai sao sas sat sba sbb sbg sbi sbo sbs sbt sga sgb sgg sgi sgo sgs sgt sia sib sig sii sio sis sit soa sob sog soi soo sos sot ss- ssa ssb ssg ssi sso sss sst sta stb stg sti sto sts stt taa tab tag tai tao tas tat tba tbb tbg tbi tbo tbs tbt tga tgb tgg tgi tgo tgs tgt tia tib tig tii tio tis tit to- toa tob tog toi too tos tot tsa tsb tsg tsi tso tss tst tta ttb ttg tti tto tts ttt