a-a a-b a-i aaa aab aad aaf aai aak aao aar ab- aba abb abd abf abi abk abo abr ad- ada adb add adf adi adk ado adr af- afa afb afd aff afi afk afo afr ai- aia aib aid aif aii aik aio air aka akb akd aki akk ako akr aoa aob aod aof aoi aok aoo aor ar- ara arb ard arf ari ark aro arr baa bab bad baf bai bak bao bar bba bbb bbd bbf bbi bbk bbo bbr bda bdb bdd bdf bdi bdk bdo bdr bfa bfb bfd bff bfi bfo bfr bi- bia bib bid bif bii bik bio bir bka bkb bkf bkk bko bkr boa bob bod bof boi bok boo bor bra brb brd brf bri brk bro brr daa dab dad daf dai dak dao dar dba dbb dbd dbf dbi dbk dbo dbr dda ddb ddd ddf ddi ddk ddo ddr dfa dfb dfd dff dfi dfk dfo dfr di- dia dib did dif dii dik dio dir dka dkb dki dkk dko dkr doa dob dod dof doi dok doo dor dra drb drd dri drk dro drr faa fab fad faf fai fak fao far fba fbb fbd fbf fbi fbk fbo fbr fda fdb fdd fdf fdi fdk fdo fdr ffa ffd fff ffi ffk ffo ffr fia fib fid fif fii fik fir fka fkb fkf fki fkk foa fob fof foi fok foo for fra frb frd frf fri frk fro frr i-d i-f ia- iaa iab iad iaf iai iao iar iba ibb ibd ibf ibi ibk ibo ibr ida idb idd idf idi idk ido idr ifa ifb ifd iff ifi ifo ifr iia iib iid iif iii iio iir ika ikb ikf iki ikk iko ikr io- ioa iob iod iof ioi ioo ior ir- ira irb ird irf iri irk iro irr ka- kaa kab kad kaf kai kak kao kar kba kbb kbd kbf kbi kbk kbo kbr kda kdb kdf kdk kdo kdr kfa kfd kff kfi kfo kia kib kid kif kii kik kio kir kkb kki kkk kkr koa kob kod kof koi kok koo kor kra krd krf kri krk kro krr o-i oaa oab oad oaf oai oak oao oar ob- oba obb obd obf obi obk obo obr oda odb odd odf odi odo odr of- ofa ofb ofd off ofi ofo ofr oia oib oid oif oii oik oio oir oka okb okd oki okk oko okr oo- ooa oob ood oof ooi ook ooo oor or- ora orb ord orf ori ork oro orr ra- raa rab rad raf rai rak rao rar rba rbb rbd rbf rbi rbk rbo rbr rda rdb rdd rdf rdi rdo rdr rfa rfb rfd rff rfi rfk rfo rfr ria rib rid rif rii rik rio rir rkb rkf rkk rko roa rob rod rof roi rok roo ror rra rrb rrd rrf rri rrk rrr