-er a-a a-b a-i aaa aab aae aai aan aar aas ab- aba abb abe abi abn abr abs aea aeb aee aei aen aer aes ai- aia aib aie aii ain air ais an- ana anb ane ani ann anr ans ar- ara arb are ari arn arr ars as- asa asb ase asi asn asr ass baa bab bae bai ban bar bas bba bbb bbe bbi bbn bbr bbs be- bea beb bee bei ben ber bes bi- bia bib bie bii bin bir bis bna bnb bne bni bnn bnr bns bra brb bre bri brn brr brs bsa bsb bse bsi bsn bsr bss eaa eab eae eai ean ear eas eba ebb ebe ebi ebn ebr ebs eea eeb eee een eer ees eia eib eie eii ein eir eis en- ena enb ene eni enn enr ens era erb ere eri ern err ers es- esa esb ese esi esn esr ess ia- iaa iab iae iai ian iar ias iba ibb ibe ibi ibn ibr ibs ie- iea iee iei ien ier ies iia iib iie iii iin iir iis in- ina inb ine ini inn inr ins ir- ira irb ire iri irn irr irs is- isa isb ise isi isn isr iss n-i naa nab nae nai nan nar nas nba nbb nbe nbi nbn nbr nbs ne- nea neb nee nei nen ner nes nia nib nie nii nin nir nis nna nnb nne nni nnn nns nra nrb nre nri nrn nrr nrs nsa nsb nse nsi nsn nsr nss ra- raa rab rae rai ran rar ras rba rbb rbe rbi rbn rbr rbs re- rea reb ree rei ren rer res ria rib rie rii rin rir ris rna rnb rni rnn rnr rns rra rrb rri rrn rrr rrs rsa rsb rse rsi rsn rsr rss saa sab sae sai san sar sas sba sbb sbe sbi sbn sbr sbs se- sea seb see sei sen ser ses sia sib sie sii sin sir sis sna snb sne sni snn snr sns sr- sra srb sre sri srn srr srs ss- ssa ssb sse ssi ssn ssr sss