-er a-a a-b a-i aaa aab aae aag aai aao aar aas ab- aba abb abe abg abi abo abr abs aea aeb aee aeg aei aeo aer aes ag- aga agb age agg agi ago agr ags ai- aia aib aie aig aii aio air ais aoa aob aoe aog aoi aoo aor aos ar- ara arb are arg ari aro arr ars as- asa asb ase asg asi aso asr ass baa bab bae bag bai bao bar bas bba bbb bbe bbg bbi bbo bbr bbs be- bea beb bee beg bei beo ber bes bga bgb bge bgg bgi bgo bgr bgs bi- bia bib bie big bii bio bir bis boa bob boe bog boi boo bor bos bra brb bre brg bri bro brr brs bsa bsb bse bsg bsi bso bsr bss eaa eab eae eag eai eao ear eas eba ebb ebe ebg ebi ebo ebr ebs eea eeb eee eeg eeo eer ees ega egb ege egg egi ego egr egs eia eib eie eig eii eio eir eis eo- eoa eob eoe eog eoi eoo eor eos era erb ere erg eri ero err ers es- esa esb ese esg esi eso esr ess gaa gab gae gag gai gao gar gas gba gbe gbg gbi gbo gbr gbs ge- gea geb gee geg gei geo ger ges gga ggb ggg ggi ggo ggr ggs gia gib gie gig gii gio gir gis goa gob goe gog goi goo gor gos gra grb gre grg gri gro grr grs gsa gsb gse gsg gsi gso gsr gss ia- iaa iab iae iag iai iao iar ias iba ibb ibe ibg ibi ibo ibr ibs ie- iea iee ieg iei ier ies iga igb ige igg igi igo igr igs iia iib iie iii iio iir iis io- ioa iob ioe iog ioi ioo ior ios ir- ira irb ire irg iri iro irr irs is- isa isb ise isg isi iso isr iss o-i oaa oab oae oag oai oao oar oas ob- oba obb obe obg obi obo obr obs oea oeb oee oeg oei oeo oer oes oga oge ogg ogi ogo ogs oia oib oie oii oio oir ois oo- ooa oob oog ooi ooo oor oos or- ora orb ore org ori oro orr ors os- osa osb ose osg osi oso osr oss ra- raa rab rae rag rai rao rar ras rba rbb rbe rbg rbi rbo rbr rbs re- rea reb ree reg rei reo rer res rga rgb rge rgg rgi rgo rgr rgs ria rib rie rig rii rio rir ris roa rob roe rog roi roo ror ros rra rrb rrg rri rrr rrs rsa rsb rse rsg rsi rso rsr rss saa sab sae sag sai sao sar sas sba sbb sbe sbg sbi sbo sbr sbs se- sea seb see seg sei seo ser ses sga sgb sge sgg sgi sgo sgr sgs sia sib sie sig sii sio sir sis soa sob soe sog soi soo sor sos sr- sra srb sre srg sri sro srr srs ss- ssa ssb sse ssg ssi sso ssr sss