-er a-a a-b aaa aab aae aam aan aao aar aas ab- aba abb abe abm abn abo abr abs aea aeb aee aem aen aeo aer aes ama amb ame amm amn amo amr ams an- ana anb ane anm ann ano anr ans aoa aob aoe aom aon aoo aor aos ar- ara arb are arm arn aro arr ars as- asa asb ase asm asn aso asr ass baa bab bae bam ban bao bar bas bba bbb bbe bbm bbn bbo bbr bbs be- bea beb bee bem ben beo ber bes bma bmb bme bmm bmn bmo bmr bms bna bnb bne bnn bno bnr bns boa bob boe bom bon boo bor bos bra brb bre brm brn bro brr brs bsa bsb bse bsm bsn bso bsr bss eaa eab eae eam ean eao ear eas eba ebb ebe ebm ebn ebo ebr ebs eea eeb eee eem een eeo eer ees em- ema emb eme emm emn emo emr ems en- ena enb ene enm enn eno enr ens eo- eoa eob eoe eom eon eoo eor eos era erb ere erm ern ero err ers es- esa esb ese esm esn eso esr ess m-o m-r maa mab mae mam man mao mar mas mba mbb mbe mbm mbo mbr mbs mea meb mee mem men meo mer mes mma mmb mme mmm mmn mmo mmr mms mna mnb mne mnm mnn mno mnr mns moa mob moe mom mon moo mor mos mra mrb mre mrm mrn mro mrr mrs msa msb mse msm msn mso msr mss naa nab nae nam nan nao nar nas nba nbb nbe nbm nbn nbo nbr nbs ne- nea neb nee nem nen neo ner nes nma nmb nme nmm nmn nmo nmr nms nna nnb nne nnm nnn nno nns no- noa nob noe nom non noo nor nos nra nrb nre nrm nrn nro nrr nrs nsa nsb nse nsm nsn nso nsr nss oaa oab oae oam oan oao oar oas ob- oba obb obe obm obn obo obr obs oea oeb oee oem oen oeo oer oes om- oma omb ome omm omn omo omr oms on- ona onb one onn ono onr ons oo- ooa oob oom oon ooo oor oos or- ora orb ore orm orn oro orr ors os- osa osb ose osm osn oso osr oss ra- raa rab rae ram ran rao rar ras rba rbb rbe rbm rbn rbo rbr rbs re- rea reb ree rem ren reo rer res rma rmb rme rmm rmn rmo rmr rms rna rnb rnm rnn rno rnr rns roa rob roe rom ron roo ror ros rra rrb rrm rrn rrr rrs rsa rsb rse rsm rsn rso rsr rss saa sab sae sam san sao sar sas sba sbb sbe sbm sbn sbo sbr sbs se- sea seb see sem sen seo ser ses sma smb sme smm smn smo smr sms sna snb sne snm snn sno snr sns soa sob soe som son soo sor sos sr- sra srb sre srm srn sro srr srs ss- ssa ssb sse ssm ssn sso ssr sss