-er a-a a-b a-i a-t aaa aab aae aaf aai aao aar aas aat ab- aba abb abe abf abi abo abr abs abt aea aeb aee aef aei aeo aer aes aet af- afa afb afe aff afi afo afr afs aft ai- aia aib aie aif aii aio air ais ait aoa aob aoe aof aoi aoo aor aos aot ar- ara arb are arf ari aro arr ars art as- asa asb ase asf asi aso asr ass ast at- ata atb ate atf ati ato atr ats att baa bab bae baf bai bao bar bas bat bba bbb bbe bbf bbi bbo bbr bbs bbt be- bea beb bee bef bei beo ber bes bet bfa bfb bfe bff bfi bfo bfr bfs bft bi- bia bib bie bif bii bio bir bis bit boa bob boe bof boi boo bor bos bot bra brb bre brf bri bro brr brs brt bsa bsb bse bsf bsi bso bsr bss bst bta btb bte btf bti bto btr bts btt eaa eab eae eaf eai eao ear eas eat eba ebb ebe ebf ebi ebo ebr ebs ebt eea eeb eee eef eeo eer ees eet ef- efa efb efe eff efi efo efr efs eft eia eib eie eif eii eio eir eis eit eo- eoa eob eoe eof eoi eoo eor eos eot era erb ere erf eri ero err ers ert es- esa esb ese esf esi eso esr ess est eta etb ete etf eti eto etr ets ett faa fab fae faf fai fao far fas fat fba fbb fbe fbf fbi fbo fbr fbs fbt fea feb fee fef fei feo fer fes fet ffa ffe fff ffi ffo ffr ffs fft fia fib fie fif fii fir fis fit foa fob foe fof foi foo for fos fot fra frb fre frf fri fro frr frs frt fsa fsb fse fsf fsi fso fsr fss fst fta ftb fte ftf fti fto ftr fts ftt i-f ia- iaa iab iae iaf iai iao iar ias iat iba ibb ibe ibf ibi ibo ibr ibs ibt ie- iea iee ief iei ier ies iet ifa ifb ife iff ifi ifo ifr ifs ift iia iib iie iif iii iio iir iis iit io- ioa iob ioe iof ioi ioo ior ios iot ir- ira irb ire irf iri iro irr irs irt is- isa isb ise isf isi iso isr iss ist ita itb ite itf iti ito its itt o-i oaa oab oae oaf oai oao oar oas oat ob- oba obb obe obf obi obo obr obs obt oea oeb oee oef oei oeo oer oes oet of- ofa ofb ofe off ofi ofo ofr ofs oft oia oib oie oif oii oio oir ois oit oo- ooa oob oof ooi ooo oor oos oot or- ora orb ore orf ori oro orr ors ort os- osa osb ose osf osi oso osr oss ost ot- ota otb ote otf oti oto otr ots ott ra- raa rab rae raf rai rao rar ras rat rba rbb rbe rbf rbi rbo rbr rbs rbt re- rea reb ree ref rei reo rer res ret rfa rfb rfe rff rfi rfo rfr rfs rft ria rib rie rif rii rio rir ris rit roa rob roe rof roi roo ror ros rot rra rrb rrf rri rrr rrs rrt rsa rsb rse rsf rsi rso rsr rss rst rta rtb rte rtf rti rto rtr rts rtt saa sab sae saf sai sao sar sas sat sba sbb sbe sbf sbi sbo sbr sbs sbt se- sea seb see sef sei seo ser ses set sfa sfb sfe sff sfi sfo sfr sfs sft sia sib sie sif sii sio sir sis sit soa sob soe sof soi soo sor sos sot sr- sra srb sre srf sri sro srr srs srt ss- ssa ssb sse ssf ssi sso ssr sss sst sta stb ste stf sti sto str sts stt taa tab tae taf tai tao tar tas tat tba tbb tbe tbf tbi tbo tbr tbs tbt te- tea teb tee tef tei teo ter tes tet tfa tfb tfe tff tfi tfo tfr tfs tft tia tib tie tif tii tio tir tis tit to- toa tob toe tof toi too tor tos tot tra trb tre trf tri tro trr trs trt tsa tsb tse tsf tsi tso tsr tss tst tta ttb tte ttf tti tto ttr tts ttt