-er a-a a-b aaa aab aad aae aag aak aao aar ab- aba abb abd abe abg abk abo abr ad- ada adb add ade adg adk ado adr aea aeb aed aee aeg aek aeo aer ag- aga agb agd age agg agk ago agr aka akb akd ake akg akk ako akr aoa aob aod aoe aog aok aoo aor ar- ara arb ard are arg ark aro arr baa bab bad bae bag bak bao bar bba bbb bbd bbe bbg bbk bbo bbr bda bdb bdd bde bdg bdk bdo bdr be- bea beb bed bee beg bek beo ber bga bgb bgd bge bgg bgk bgo bgr bka bkb bke bkg bkk bko bkr boa bob bod boe bog bok boo bor bra brb brd bre brg brk bro brr daa dab dad dae dag dak dao dar dba dbb dbd dbe dbg dbk dbo dbr dda ddb ddd dde ddg ddk ddo ddr de- dea deb ded dee deg dek deo der dga dgd dge dgg dgk dgr dka dkb dke dkg dkk dko dkr doa dob dod doe dog dok doo dor dra drb drd dre drg drk dro drr eaa eab ead eae eag eak eao ear eba ebb ebd ebe ebg ebk ebo ebr ed- eda edb edd ede edg edk edo edr eea eeb eed eee eeg eek eeo eer ega egb egd ege egg ego egr eka ekb ekd eke ekg eko ekr eo- eoa eob eod eoe eog eok eoo eor era erb erd ere erg erk ero err g-d gaa gab gad gae gag gak gao gar gba gbd gbe gbg gbk gbo gbr gda gdb gdd gde gdk gdo gdr ge- gea geb ged gee geg gek geo ger gga ggb ggd ggg ggo ggr gka gkb gkd gko goa gob god goe gog gok goo gor gra grb grd gre grg grk gro grr ka- kaa kab kad kae kag kak kao kar kba kbb kbd kbe kbk kbo kbr kda kdb kde kdg kdk kdo kdr ke- kea keb ked kee keg kek keo ker kga kgb kgd kgo kkb kke kkk kkr koa kob kod koe kog kok koo kor kra krd krg krk kro krr oaa oab oad oae oag oak oao oar ob- oba obb obd obe obg obk obo obr oda odb odd ode odg odo odr oea oeb oed oee oeg oeo oer oga ogd oge ogg ogo oka okb okd oke okg okk oko okr oo- ooa oob ood oog ook ooo oor or- ora orb ord ore org ork oro orr ra- raa rab rad rae rag rak rao rar rba rbb rbd rbe rbg rbk rbo rbr rda rdb rdd rde rdg rdo rdr re- rea reb red ree reg rek reo rer rga rgb rgd rge rgg rgk rgo rgr rkb rke rkg rkk rko roa rob rod roe rog rok roo ror rra rrb rrd rrg rrk rrr