a-a a-b a-t aaa aab aam aao aat ab- aba abb abm abo abt ama amb amm amo amt aoa aob aom aoo aot at- ata atb atm ato att baa bab bam bao bat bba bbb bbm bbo bbt bma bmb bmm bmo bmt boa bob bom boo bot bta btb btm bto btt m-o maa mab mam mao mat mba mbb mbm mbo mbt mma mmb mmm mmo mmt moa mob mom moo mot mta mtb mtm mto mtt oaa oab oam oao oat ob- oba obb obm obo obt om- oma omb omm omo omt oo- ooa oob oom ooo oot ot- ota otb otm oto ott taa tab tam tao tat tba tbb tbm tbo tbt tma tmb tmm tmo tmt to- toa tob tom too tot tta ttb ttm tto ttt