a-a a-b aaa aab aaf aag aan aao aar aas ab- aba abb abf abg abn abo abr abs af- afa afb aff afg afn afo afr afs ag- aga agb agf agg agn ago agr ags an- ana anb anf ang ann ano anr ans aoa aob aof aog aon aoo aor aos ar- ara arb arf arg arn aro arr ars as- asa asb asf asg asn aso asr ass baa bab baf bag ban bao bar bas bba bbb bbf bbg bbn bbo bbr bbs bfa bfb bff bfg bfn bfo bfr bfs bga bgb bgf bgg bgn bgo bgr bgs bna bnb bnf bng bnn bno bnr bns boa bob bof bog bon boo bor bos bra brb brf brg brn bro brr brs bsa bsb bsf bsg bsn bso bsr bss faa fab faf fag fan fao far fas fba fbb fbf fbg fbn fbo fbr fbs ffa fff ffg ffn ffo ffr ffs fga fgb fgf fgg fgn fgr fgs fna fnb fnf fng fnn fnr fns foa fob fof fog fon foo for fos fra frb frf frg frn fro frr frs fsa fsb fsf fsg fsn fso fsr fss gaa gab gaf gag gan gao gar gas gba gbf gbg gbn gbo gbr gbs gfa gfb gff gfo gfr gfs gga ggb ggg ggn ggo ggr ggs gna gnb gnf gnn gno gnr gns goa gob gof gog gon goo gor gos gra grb grf grg grn gro grr grs gsa gsb gsf gsg gsn gso gsr gss naa nab naf nag nan nao nar nas nba nbb nbf nbg nbn nbo nbr nbs nfa nfb nff nfn nfo nfr nfs nga ngb ngf ngg ngn ngo ngs nna nnb nnf nng nnn nno nns no- noa nob nof nog non noo nor nos nra nrb nrf nrg nrn nro nrr nrs nsa nsb nsf nsg nsn nso nsr nss oaa oab oaf oag oan oao oar oas ob- oba obb obf obg obn obo obr obs of- ofa ofb off ofg ofn ofo ofr ofs oga ogf ogg ogn ogo ogs on- ona onb onf ong onn ono onr ons oo- ooa oob oof oog oon ooo oor oos or- ora orb orf org orn oro orr ors os- osa osb osf osg osn oso osr oss ra- raa rab raf rag ran rao rar ras rba rbb rbf rbg rbn rbo rbr rbs rfa rfb rff rfg rfn rfo rfr rfs rga rgb rgf rgg rgn rgo rgr rgs rna rnb rng rnn rno rnr rns roa rob rof rog ron roo ror ros rra rrb rrf rrg rrn rrr rrs rsa rsb rsf rsg rsn rso rsr rss saa sab saf sag san sao sar sas sba sbb sbf sbg sbn sbo sbr sbs sfa sfb sff sfg sfn sfo sfr sfs sga sgb sgf sgg sgn sgo sgr sgs sna snb snf sng snn sno snr sns soa sob sof sog son soo sor sos sr- sra srb srf srg srn sro srr srs ss- ssa ssb ssf ssg ssn sso ssr sss