a-a a-b aaa aab aae aaf aag aan aao aas ab- aba abb abe abf abg abn abo abs aea aeb aee aef aeg aen aeo aes af- afa afb afe aff afg afn afo afs ag- aga agb age agf agg agn ago ags an- ana anb ane anf ang ann ano ans aoa aob aoe aof aog aon aoo aos as- asa asb ase asf asg asn aso ass baa bab bae baf bag ban bao bas bba bbb bbe bbf bbg bbn bbo bbs be- bea beb bee bef beg ben beo bes bfa bfb bfe bff bfg bfn bfo bfs bga bgb bge bgf bgg bgn bgo bgs bna bnb bne bnf bng bnn bno bns boa bob boe bof bog bon boo bos bsa bsb bse bsf bsg bsn bso bss eaa eab eae eaf eag ean eao eas eba ebb ebe ebf ebg ebn ebo ebs eea eeb eee eef eeg een eeo ees ef- efa efb efe eff efg efo efs ega egb ege egf egg egn ego egs en- ena enb ene enf eng enn eno ens eo- eoa eob eoe eof eog eon eoo eos es- esa esb ese esf esg esn eso ess faa fab fae faf fag fan fao fas fba fbb fbe fbf fbg fbn fbo fbs fea feb fee fef feg fen feo fes ffa ffe fff ffg ffn ffo ffs fga fgb fge fgf fgg fgn fgs fna fnb fne fnf fng fnn fns foa fob foe fof fog fon foo fos fsa fsb fse fsf fsg fsn fso fss gaa gab gae gaf gag gan gao gas gba gbe gbf gbg gbn gbo gbs ge- gea geb gee gef geg gen geo ges gfa gfb gfe gff gfo gfs gga ggb ggg ggn ggo ggs gna gnb gne gnf gnn gno gns goa gob goe gof gog gon goo gos gsa gsb gse gsf gsg gsn gso gss naa nab nae naf nag nan nao nas nba nbb nbe nbf nbg nbn nbo nbs ne- nea neb nee nef neg nen neo nes nfa nfb nfe nff nfn nfo nfs nga ngb nge ngf ngg ngn ngo ngs nna nnb nne nnf nng nnn nno nns no- noa nob noe nof nog non noo nos nsa nsb nse nsf nsg nsn nso nss oaa oab oae oaf oag oan oao oas ob- oba obb obe obf obg obn obo obs oea oeb oee oef oeg oen oeo oes of- ofa ofb ofe off ofg ofn ofo ofs oga oge ogf ogg ogn ogo ogs on- ona onb one onf ong onn ono ons oo- ooa oob oof oog oon ooo oos os- osa osb ose osf osg osn oso oss saa sab sae saf sag san sao sas sba sbb sbe sbf sbg sbn sbo sbs se- sea seb see sef seg sen seo ses sfa sfb sfe sff sfg sfn sfo sfs sga sgb sge sgf sgg sgn sgo sgs sna snb sne snf sng snn sno sns soa sob soe sof sog son soo sos ss- ssa ssb sse ssf ssg ssn sso sss