-er a-a a-b a-i a-t aaa aab aae aaf aai aao aar aat ab- aba abb abe abf abi abo abr abt aea aeb aee aef aei aeo aer aet af- afa afb afe aff afi afo afr aft ai- aia aib aie aif aii aio air ait aoa aob aoe aof aoi aoo aor aot ar- ara arb are arf ari aro arr art at- ata atb ate atf ati ato atr att baa bab bae baf bai bao bar bat bba bbb bbe bbf bbi bbo bbr bbt be- bea beb bee bef bei beo ber bet bfa bfb bfe bff bfi bfo bfr bft bi- bia bib bie bif bii bio bir bit boa bob boe bof boi boo bor bot bra brb bre brf bri bro brr brt bta btb bte btf bti bto btr btt eaa eab eae eaf eai eao ear eat eba ebb ebe ebf ebi ebo ebr ebt eea eeb eee eef eeo eer eet ef- efa efb efe eff efi efo efr eft eia eib eie eif eii eio eir eit eo- eoa eob eoe eof eoi eoo eor eot era erb ere erf eri ero err ert eta etb ete etf eti eto etr ett faa fab fae faf fai fao far fat fba fbb fbe fbf fbi fbo fbr fbt fea feb fee fef fei feo fer fet ffa ffe fff ffi ffo ffr fft fia fib fie fif fii fir fit foa fob foe fof foi foo for fot fra frb fre frf fri fro frr frt fta ftb fte ftf fti fto ftr ftt i-f ia- iaa iab iae iaf iai iao iar iat iba ibb ibe ibf ibi ibo ibr ibt ie- iea iee ief iei ier iet ifa ifb ife iff ifi ifo ifr ift iia iib iie iif iii iio iir iit io- ioa iob ioe iof ioi ioo ior iot ir- ira irb ire irf iri iro irr irt ita itb ite itf iti ito itt o-i oaa oab oae oaf oai oao oar oat ob- oba obb obe obf obi obo obr obt oea oeb oee oef oei oeo oer oet of- ofa ofb ofe off ofi ofo ofr oft oia oib oie oif oii oio oir oit oo- ooa oob oof ooi ooo oor oot or- ora orb ore orf ori oro orr ort ot- ota otb ote otf oti oto otr ott ra- raa rab rae raf rai rao rar rat rba rbb rbe rbf rbi rbo rbr rbt re- rea reb ree ref rei reo rer ret rfa rfb rfe rff rfi rfo rfr rft ria rib rie rif rii rio rir rit roa rob roe rof roi roo ror rot rra rrb rrf rri rrr rrt rta rtb rte rtf rti rto rtr rtt taa tab tae taf tai tao tar tat tba tbb tbe tbf tbi tbo tbr tbt te- tea teb tee tef tei teo ter tet tfa tfb tfe tff tfi tfo tfr tft tia tib tie tif tii tio tir tit to- toa tob toe tof toi too tor tot tra trb tre trf tri tro trr trt tta ttb tte ttf tti tto ttr ttt