-er a-a a-b aaa aab aad aae aag aao aar ab- aba abb abd abe abg abo abr ad- ada adb add ade adg ado adr aea aeb aed aee aeg aeo aer ag- aga agb agd age agg ago agr aoa aob aod aoe aog aoo aor ar- ara arb ard are arg aro arr baa bab bad bae bag bao bar bba bbb bbd bbe bbg bbo bbr bda bdb bdd bde bdg bdo bdr be- bea beb bed bee beg beo ber bga bgb bgd bge bgg bgo bgr boa bob bod boe bog boo bor bra brb brd bre brg bro brr daa dab dad dae dag dao dar dba dbb dbd dbe dbg dbo dbr dda ddb ddd dde ddg ddo ddr de- dea deb ded dee deg deo der dga dgd dge dgg dgr doa dob dod doe dog doo dor dra drb drd dre drg dro drr eaa eab ead eae eag eao ear eba ebb ebd ebe ebg ebo ebr ed- eda edb edd ede edg edo edr eea eeb eed eee eeg eeo eer ega egb egd ege egg ego egr eo- eoa eob eod eoe eog eoo eor era erb erd ere erg ero err g-d gaa gab gad gae gag gao gar gba gbd gbe gbg gbo gbr gda gdb gdd gde gdo gdr ge- gea geb ged gee geg geo ger gga ggb ggd ggg ggo ggr goa gob god goe gog goo gor gra grb grd gre grg gro grr oaa oab oad oae oag oao oar ob- oba obb obd obe obg obo obr oda odb odd ode odg odo odr oea oeb oed oee oeg oeo oer oga ogd oge ogg ogo oo- ooa oob ood oog ooo oor or- ora orb ord ore org oro orr ra- raa rab rad rae rag rao rar rba rbb rbd rbe rbg rbo rbr rda rdb rdd rde rdg rdo rdr re- rea reb red ree reg reo rer rga rgb rgd rge rgg rgo rgr roa rob rod roe rog roo ror rra rrb rrd rrg rrr