a-a a-b aaa aab aam aao aar aax ab- aba abb abm abo abr abx ama amb amm amo amr amx aoa aob aom aoo aor aox ar- ara arb arm aro arr arx ax- axa axm axo axr axx baa bab bam bao bar bax bba bbb bbm bbo bbr bbx bma bmb bmm bmo bmr bmx boa bob bom boo bor box bra brb brm bro brr brx bxb bxm bxo bxx m-o m-r maa mab mam mao mar max mba mbb mbm mbo mbr mbx mma mmb mmm mmo mmr mmx moa mob mom moo mor mox mra mrb mrm mro mrr mrx mxa mxr oaa oab oam oao oar oax ob- oba obb obm obo obr obx om- oma omb omm omo omr omx oo- ooa oob oom ooo oor oox or- ora orb orm oro orr orx ox- oxa oxb oxo oxx ra- raa rab ram rao rar rax rba rbb rbm rbo rbr rbx rma rmb rmm rmo rmr rmx roa rob rom roo ror rox rra rrb rrm rrr rxr xaa xam xar xbr xbx xma xmm xmo xmr xmx xoa xom xoo xor xox xrx xxo xxx