a-a a-b a-t aaa aab aaf aam aao aat ab- aba abb abf abm abo abt af- afa afb aff afm afo aft ama amb amf amm amo amt aoa aob aof aom aoo aot at- ata atb atf atm ato att baa bab baf bam bao bat bba bbb bbf bbm bbo bbt bfa bfb bff bfm bfo bft bma bmb bmf bmm bmo bmt boa bob bof bom boo bot bta btb btf btm bto btt faa fab faf fam fao fat fba fbb fbf fbm fbo fbt ffa fff ffm ffo fft fma fmb fmf fmm fmo fmt foa fob fof fom foo fot fta ftb ftf ftm fto ftt m-f m-o maa mab maf mam mao mat mba mbb mbf mbm mbo mbt mfa mfb mff mfm mfo mft mma mmb mmf mmm mmo mmt moa mob mof mom moo mot mta mtb mtf mtm mto mtt oaa oab oaf oam oao oat ob- oba obb obf obm obo obt of- ofa ofb off ofm ofo oft om- oma omb omf omm omo omt oo- ooa oob oof oom ooo oot ot- ota otb otf otm oto ott taa tab taf tam tao tat tba tbb tbf tbm tbo tbt tfa tfb tff tfm tfo tft tma tmb tmf tmm tmo tmt to- toa tob tof tom too tot tta ttb ttf ttm tto ttt