a-a a-b aaa aab aam aao aax aay ab- aba abb abm abo abx aby ama amb amm amo amx amy aoa aob aom aoo aox ax- axa axm axo axx ay- aya ayo ayx baa bab bam bao bax bay bba bbb bbm bbo bbx bby bma bmb bmm bmo bmx boa bob bom boo box boy bxb bxm bxo bxx by- bya bym byo m-o maa mab mam mao max may mba mbb mbm mbo mbx mma mmb mmm mmo mmx moa mob mom moo mox moy mxa my- mya myb mym myo myx oaa oab oam oao oax ob- oba obb obm obo obx oby om- oma omb omm omo omx omy oo- ooa oob oom ooo oox ox- oxa oxb oxo oxx oxy oya oyo xaa xam xbx xma xmm xmo xmx xoa xom xoo xox xxo xxx xxy xyy yaa yab yam yao yax yay ybm yby yma ymm ymo yob yom yoo yox yoy yxa yxy yyb yyy