a-a a-b a-t aaa aab aam aao aar aat ab- aba abb abm abo abr abt ama amb amm amo amr amt aoa aob aom aoo aor aot ar- ara arb arm aro arr art at- ata atb atm ato atr att baa bab bam bao bar bat bba bbb bbm bbo bbr bbt bma bmb bmm bmo bmr bmt boa bob bom boo bor bot bra brb brm bro brr brt bta btb btm bto btr btt m-o m-r maa mab mam mao mar mat mba mbb mbm mbo mbr mbt mma mmb mmm mmo mmr mmt moa mob mom moo mor mot mra mrb mrm mro mrr mrt mta mtb mtm mto mtr mtt oaa oab oam oao oar oat ob- oba obb obm obo obr obt om- oma omb omm omo omr omt oo- ooa oob oom ooo oor oot or- ora orb orm oro orr ort ot- ota otb otm oto otr ott ra- raa rab ram rao rar rat rba rbb rbm rbo rbr rbt rma rmb rmm rmo rmr rmt roa rob rom roo ror rot rra rrb rrm rrr rrt rta rtb rtm rto rtr rtt taa tab tam tao tar tat tba tbb tbm tbo tbr tbt tma tmb tmm tmo tmr tmt to- toa tob tom too tor tot tra trb trm tro trr trt tta ttb ttm tto ttr ttt