a-a a-b aaa aab aad aaf aam aao aar ab- aba abb abd abf abm abo abr ad- ada adb add adf adm ado adr af- afa afb afd aff afm afo afr ama amb amd amf amm amo amr aoa aob aod aof aom aoo aor ar- ara arb ard arf arm aro arr baa bab bad baf bam bao bar bba bbb bbd bbf bbm bbo bbr bda bdb bdd bdf bdm bdo bdr bfa bfb bfd bff bfm bfo bfr bma bmb bmd bmf bmm bmo bmr boa bob bod bof bom boo bor bra brb brd brf brm bro brr daa dab dad daf dam dao dar dba dbb dbd dbf dbm dbo dbr dda ddb ddd ddf ddm ddo ddr dfa dfb dfd dff dfm dfo dfr dma dmb dmd dmf dmm dmo dmr doa dob dod dof dom doo dor dra drb drd drm dro drr faa fab fad faf fam fao far fba fbb fbd fbf fbm fbo fbr fda fdb fdd fdf fdm fdo fdr ffa ffd fff ffm ffo ffr fma fmb fmd fmf fmm fmo fmr foa fob fof fom foo for fra frb frd frf frm fro frr m-f m-o m-r maa mab mad maf mam mao mar mba mbb mbd mbf mbm mbo mbr mda mdb mdd mdf mdm mdo mdr mfa mfb mfd mff mfm mfo mfr mma mmb mmd mmf mmm mmo mmr moa mob mod mof mom moo mor mra mrb mrd mrf mrm mro mrr oaa oab oad oaf oam oao oar ob- oba obb obd obf obm obo obr oda odb odd odf odm odo odr of- ofa ofb ofd off ofm ofo ofr om- oma omb omd omf omm omo omr oo- ooa oob ood oof oom ooo oor or- ora orb ord orf orm oro orr ra- raa rab rad raf ram rao rar rba rbb rbd rbf rbm rbo rbr rda rdb rdd rdf rdm rdo rdr rfa rfb rfd rff rfm rfo rfr rma rmb rmd rmf rmm rmo rmr roa rob rod rof rom roo ror rra rrb rrd rrf rrm rrr