-er a-a a-b a-i aaa aab aad aae aai aao aar ab- aba abb abd abe abi abo abr ad- ada adb add ade adi ado adr aea aeb aed aee aei aeo aer ai- aia aib aid aie aii aio air aoa aob aod aoe aoi aoo aor ar- ara arb ard are ari aro arr baa bab bad bae bai bao bar bba bbb bbd bbe bbi bbo bbr bda bdb bdd bde bdi bdo bdr be- bea beb bed bee bei beo ber bi- bia bib bid bie bii bio bir boa bob bod boe boi boo bor bra brb brd bre bri bro brr daa dab dad dae dai dao dar dba dbb dbd dbe dbi dbo dbr dda ddb ddd dde ddi ddo ddr de- dea deb ded dee dei deo der di- dia dib did die dii dio dir doa dob dod doe doi doo dor dra drb drd dre dri dro drr eaa eab ead eae eai eao ear eba ebb ebd ebe ebi ebo ebr ed- eda edb edd ede edi edo edr eea eeb eed eee eeo eer eia eib eid eie eii eio eir eo- eoa eob eod eoe eoi eoo eor era erb erd ere eri ero err i-d ia- iaa iab iad iae iai iao iar iba ibb ibd ibe ibi ibo ibr ida idb idd ide idi ido idr ie- iea ied iee iei ier iia iib iid iie iii iio iir io- ioa iob iod ioe ioi ioo ior ir- ira irb ird ire iri iro irr o-i oaa oab oad oae oai oao oar ob- oba obb obd obe obi obo obr oda odb odd ode odi odo odr oea oeb oed oee oei oeo oer oia oib oid oie oii oio oir oo- ooa oob ood ooi ooo oor or- ora orb ord ore ori oro orr ra- raa rab rad rae rai rao rar rba rbb rbd rbe rbi rbo rbr rda rdb rdd rde rdi rdo rdr re- rea reb red ree rei reo rer ria rib rid rie rii rio rir roa rob rod roe roi roo ror rra rrb rrd rri rrr