-er a-a a-b aaa aab aae aag aan aao aar aas ab- aba abb abe abg abn abo abr abs aea aeb aee aeg aen aeo aer aes ag- aga agb age agg agn ago agr ags an- ana anb ane ang ann ano anr ans aoa aob aoe aog aon aoo aor aos ar- ara arb are arg arn aro arr ars as- asa asb ase asg asn aso asr ass baa bab bae bag ban bao bar bas bba bbb bbe bbg bbn bbo bbr bbs be- bea beb bee beg ben beo ber bes bga bgb bge bgg bgn bgo bgr bgs bna bnb bne bng bnn bno bnr bns boa bob boe bog bon boo bor bos bra brb bre brg brn bro brr brs bsa bsb bse bsg bsn bso bsr bss eaa eab eae eag ean eao ear eas eba ebb ebe ebg ebn ebo ebr ebs eea eeb eee eeg een eeo eer ees ega egb ege egg egn ego egr egs en- ena enb ene eng enn eno enr ens eo- eoa eob eoe eog eon eoo eor eos era erb ere erg ern ero err ers es- esa esb ese esg esn eso esr ess gaa gab gae gag gan gao gar gas gba gbe gbg gbn gbo gbr gbs ge- gea geb gee geg gen geo ger ges gga ggb ggg ggn ggo ggr ggs gna gnb gne gnn gno gnr gns goa gob goe gog gon goo gor gos gra grb gre grg grn gro grr grs gsa gsb gse gsg gsn gso gsr gss naa nab nae nag nan nao nar nas nba nbb nbe nbg nbn nbo nbr nbs ne- nea neb nee neg nen neo ner nes nga ngb nge ngg ngn ngo ngs nna nnb nne nng nnn nno nns no- noa nob noe nog non noo nor nos nra nrb nre nrg nrn nro nrr nrs nsa nsb nse nsg nsn nso nsr nss oaa oab oae oag oan oao oar oas ob- oba obb obe obg obn obo obr obs oea oeb oee oeg oen oeo oer oes oga oge ogg ogn ogo ogs on- ona onb one ong onn ono onr ons oo- ooa oob oog oon ooo oor oos or- ora orb ore org orn oro orr ors os- osa osb ose osg osn oso osr oss ra- raa rab rae rag ran rao rar ras rba rbb rbe rbg rbn rbo rbr rbs re- rea reb ree reg ren reo rer res rga rgb rge rgg rgn rgo rgr rgs rna rnb rng rnn rno rnr rns roa rob roe rog ron roo ror ros rra rrb rrg rrn rrr rrs rsa rsb rse rsg rsn rso rsr rss saa sab sae sag san sao sar sas sba sbb sbe sbg sbn sbo sbr sbs se- sea seb see seg sen seo ser ses sga sgb sge sgg sgn sgo sgr sgs sna snb sne sng snn sno snr sns soa sob soe sog son soo sor sos sr- sra srb sre srg srn sro srr srs ss- ssa ssb sse ssg ssn sso ssr sss