-er a-a a-b a-t aaa aab aae aan aao aar aas aat ab- aba abb abe abn abo abr abs abt aea aeb aee aen aeo aer aes aet an- ana anb ane ann ano anr ans ant aoa aob aoe aon aoo aor aos aot ar- ara arb are arn aro arr ars art as- asa asb ase asn aso asr ass ast at- ata atb ate atn ato atr ats att baa bab bae ban bao bar bas bat bba bbb bbe bbn bbo bbr bbs bbt be- bea beb bee ben beo ber bes bet bna bnb bne bnn bno bnr bns bnt boa bob boe bon boo bor bos bot bra brb bre brn bro brr brs brt bsa bsb bse bsn bso bsr bss bst bta btb bte btn bto btr bts btt eaa eab eae ean eao ear eas eat eba ebb ebe ebn ebo ebr ebs ebt eea eeb eee een eeo eer ees eet en- ena enb ene enn eno enr ens ent eo- eoa eob eoe eon eoo eor eos eot era erb ere ern ero err ers ert es- esa esb ese esn eso esr ess est eta etb ete etn eto etr ets ett naa nab nae nan nao nar nas nat nba nbb nbe nbn nbo nbr nbs nbt ne- nea neb nee nen neo ner nes net nna nnb nne nnn nno nns nnt no- noa nob noe non noo nor nos not nra nrb nre nrn nro nrr nrs nrt nsa nsb nse nsn nso nsr nss nst nta ntb nte ntn nto ntr nts ntt oaa oab oae oan oao oar oas oat ob- oba obb obe obn obo obr obs obt oea oeb oee oen oeo oer oes oet on- ona onb one onn ono onr ons ont oo- ooa oob oon ooo oor oos oot or- ora orb ore orn oro orr ors ort os- osa osb ose osn oso osr oss ost ot- ota otb ote otn oto otr ots ott ra- raa rab rae ran rao rar ras rat rba rbb rbe rbn rbo rbr rbs rbt re- rea reb ree ren reo rer res ret rna rnb rnn rno rnr rns rnt roa rob roe ron roo ror ros rot rra rrb rrn rrr rrs rrt rsa rsb rse rsn rso rsr rss rst rta rtb rte rtn rto rtr rts rtt saa sab sae san sao sar sas sat sba sbb sbe sbn sbo sbr sbs sbt se- sea seb see sen seo ser ses set sna snb sne snn sno snr sns snt soa sob soe son soo sor sos sot sr- sra srb sre srn sro srr srs srt ss- ssa ssb sse ssn sso ssr sss sst sta stb ste stn sto str sts stt taa tab tae tan tao tar tas tat tba tbb tbe tbn tbo tbr tbs tbt te- tea teb tee ten teo ter tes tet tna tnb tne tnn tno tnr tns tnt to- toa tob toe ton too tor tos tot tra trb tre trn tro trr trs trt tsa tsb tse tsn tso tsr tss tst tta ttb tte ttn tto ttr tts ttt