-er a-a a-b a-c aaa aab aac aad aae aag aao aar ab- aba abb abc abd abe abg abo abr ac- aca acb acc acd ace acg aco acr ad- ada adb adc add ade adg ado adr aea aeb aec aed aee aeg aeo aer ag- aga agb agc agd age agg ago agr aoa aob aoc aod aoe aog aoo aor ar- ara arb arc ard are arg aro arr baa bab bac bad bae bag bao bar bba bbb bbc bbd bbe bbg bbo bbr bca bcb bcc bcd bce bcg bco bcr bda bdb bdc bdd bde bdg bdo bdr be- bea beb bec bed bee beg beo ber bga bgb bgc bgd bge bgg bgo bgr boa bob boc bod boe bog boo bor bra brb brd bre brg bro brr c-- caa cab cac cad cae cag cao car cba cbb cbc cbd cbe cbg cbo cbr cca ccb ccc ccd cce ccg cco ccr cda cdb cdc cdd cde cdg cdo cdr ce- cea ceb cec ced cee ceg ceo cer cga cgb cgc cgd cge cgg cgo cgr co- coa cob coc cod coe cog coo cor cra crb crc crd cre crg cro crr daa dab dac dad dae dag dao dar dba dbb dbc dbd dbe dbg dbo dbr dca dcb dcc dcd dce dcg dco dcr dda ddb ddc ddd dde ddg ddo ddr de- dea deb dec ded dee deg deo der dga dgc dgd dge dgg dgr doa dob doc dod doe dog doo dor dra drb drc drd dre drg dro drr eaa eab eac ead eae eag eao ear eba ebb ebc ebd ebe ebg ebo ebr ec- eca ecb ecc ecd ece ecg eco ecr ed- eda edb edc edd ede edg edo edr eea eeb eec eed eee eeg eeo eer ega egb egc egd ege egg ego egr eo- eoa eob eoc eod eoe eog eoo eor era erb erc erd ere erg ero err g-d gaa gab gac gad gae gag gao gar gba gbc gbd gbe gbg gbo gbr gca gcb gcc gcd gce gcg gco gcr gda gdb gdc gdd gde gdo gdr ge- gea geb gec ged gee geg geo ger gga ggb ggc ggd ggg ggo ggr goa gob goc god goe gog goo gor gra grb grc grd gre grg gro grr oaa oab oac oad oae oag oao oar ob- oba obb obc obd obe obg obo obr oc- oca ocb occ ocd ocg oco ocr oda odb odc odd ode odg odo odr oea oeb oec oed oee oeg oeo oer oga ogc ogd oge ogg ogo oo- ooa oob ooc ood oog ooo oor or- ora orb orc ord ore org oro orr ra- raa rab rac rad rae rag rao rar rba rbb rbc rbd rbe rbg rbo rbr rca rcb rcc rcd rce rcg rco rcr rda rdb rdc rdd rde rdg rdo rdr re- rea reb rec red ree reg reo rer rga rgb rgc rgd rge rgg rgo rgr roa rob roc rod roe rog roo ror rra rrb rrc rrd rrg rrr