a-a a-b a-i aaa aab aad aai aao aar ab- aba abb abd abi abo abr ad- ada adb add adi ado adr ai- aia aib aid aii aio air aoa aob aod aoi aoo aor ar- ara arb ard ari aro arr baa bab bad bai bao bar bba bbb bbd bbi bbo bbr bda bdb bdd bdi bdo bdr bi- bia bib bid bii bio bir boa bob bod boi boo bor bra brb brd bri bro brr daa dab dad dai dao dar dba dbb dbd dbi dbo dbr dda ddb ddd ddi ddo ddr di- dia dib did dii dio dir doa dob dod doi doo dor dra drb drd dri dro drr i-d ia- iaa iab iad iai iao iar iba ibb ibd ibi ibo ibr ida idb idd idi ido idr iia iib iid iii iio iir io- ioa iob iod ioi ioo ior ir- ira irb ird iri iro irr o-i oaa oab oad oai oao oar ob- oba obb obd obi obo obr oda odb odd odi odo odr oia oib oid oii oio oir oo- ooa oob ood ooi ooo oor or- ora orb ord ori oro orr ra- raa rab rad rai rao rar rba rbb rbd rbi rbo rbr rda rdb rdd rdi rdo rdr ria rib rid rii rio rir roa rob rod roi roo ror rra rrb rrd rri rrr