a-a a-b a-i aaa aab aag aai aao aar aas ab- aba abb abg abi abo abr abs ag- aga agb agg agi ago agr ags ai- aia aib aig aii aio air ais aoa aob aog aoi aoo aor aos ar- ara arb arg ari aro arr ars as- asa asb asg asi aso asr ass baa bab bag bai bao bar bas bba bbb bbg bbi bbo bbr bbs bga bgb bgg bgi bgo bgr bgs bi- bia bib big bii bio bir bis boa bob bog boi boo bor bos bra brb brg bri bro brr brs bsa bsb bsg bsi bso bsr bss gaa gab gag gai gao gar gas gba gbg gbi gbo gbr gbs gga ggb ggg ggi ggo ggr ggs gia gib gig gii gio gir gis goa gob gog goi goo gor gos gra grb grg gri gro grr grs gsa gsb gsg gsi gso gsr gss ia- iaa iab iag iai iao iar ias iba ibb ibg ibi ibo ibr ibs iga igb igg igi igo igr igs iia iib iii iio iir iis io- ioa iob iog ioi ioo ior ios ir- ira irb irg iri iro irr irs is- isa isb isg isi iso isr iss o-i oaa oab oag oai oao oar oas ob- oba obb obg obi obo obr obs oga ogg ogi ogo ogs oia oib oii oio oir ois oo- ooa oob oog ooi ooo oor oos or- ora orb org ori oro orr ors os- osa osb osg osi oso osr oss ra- raa rab rag rai rao rar ras rba rbb rbg rbi rbo rbr rbs rga rgb rgg rgi rgo rgr rgs ria rib rig rii rio rir ris roa rob rog roi roo ror ros rra rrb rrg rri rrr rrs rsa rsb rsg rsi rso rsr rss saa sab sag sai sao sar sas sba sbb sbg sbi sbo sbr sbs sga sgb sgg sgi sgo sgr sgs sia sib sig sii sio sir sis soa sob sog soi soo sor sos sr- sra srb srg sri sro srr srs ss- ssa ssb ssg ssi sso ssr sss