-er a-a a-b a-i a-t aaa aab aae aag aai aao aar aat ab- aba abb abe abg abi abo abr abt aea aeb aee aeg aei aeo aer aet ag- aga agb age agg agi ago agr agt ai- aia aib aie aig aii aio air ait aoa aob aoe aog aoi aoo aor aot ar- ara arb are arg ari aro arr art at- ata atb ate atg ati ato atr att baa bab bae bag bai bao bar bat bba bbb bbe bbg bbi bbo bbr bbt be- bea beb bee beg bei beo ber bet bga bgb bge bgg bgi bgo bgr bgt bi- bia bib bie big bii bio bir bit boa bob boe bog boi boo bor bot bra brb bre brg bri bro brr brt bta btb bte btg bti bto btr btt eaa eab eae eag eai eao ear eat eba ebb ebe ebg ebi ebo ebr ebt eea eeb eee eeg eeo eer eet ega egb ege egg egi ego egr egt eia eib eie eig eii eio eir eit eo- eoa eob eoe eog eoi eoo eor eot era erb ere erg eri ero err ert eta etb ete etg eti eto etr ett gaa gab gae gag gai gao gar gat gba gbe gbg gbi gbo gbr gbt ge- gea geb gee geg gei geo ger get gga ggb ggg ggi ggo ggr ggt gia gib gie gig gii gio gir git goa gob goe gog goi goo gor got gra grb gre grg gri gro grr grt gta gtb gte gtg gti gto gtr gtt ia- iaa iab iae iag iai iao iar iat iba ibb ibe ibg ibi ibo ibr ibt ie- iea iee ieg iei ier iet iga igb ige igg igi igo igr igt iia iib iie iii iio iir iit io- ioa iob ioe iog ioi ioo ior iot ir- ira irb ire irg iri iro irr irt ita itb ite itg iti ito itt o-i oaa oab oae oag oai oao oar oat ob- oba obb obe obg obi obo obr obt oea oeb oee oeg oei oeo oer oet oga oge ogg ogi ogo ogt oia oib oie oii oio oir oit oo- ooa oob oog ooi ooo oor oot or- ora orb ore org ori oro orr ort ot- ota otb ote otg oti oto otr ott ra- raa rab rae rag rai rao rar rat rba rbb rbe rbg rbi rbo rbr rbt re- rea reb ree reg rei reo rer ret rga rgb rge rgg rgi rgo rgr rgt ria rib rie rig rii rio rir rit roa rob roe rog roi roo ror rot rra rrb rrg rri rrr rrt rta rtb rte rtg rti rto rtr rtt taa tab tae tag tai tao tar tat tba tbb tbe tbg tbi tbo tbr tbt te- tea teb tee teg tei teo ter tet tga tgb tge tgg tgi tgo tgr tgt tia tib tie tig tii tio tir tit to- toa tob toe tog toi too tor tot tra trb tre trg tri tro trr trt tta ttb tte ttg tti tto ttr ttt