a-a a-b aaa aab aae aam aan aao ab- aba abb abe abm abn abo aea aeb aee aem aen aeo ama amb ame amm amn amo an- ana anb ane anm ann ano aoa aob aoe aom aon aoo baa bab bae bam ban bao bba bbb bbe bbm bbn bbo be- bea beb bee bem ben beo bma bmb bme bmm bmn bmo bna bnb bne bnn bno boa bob boe bom bon boo eaa eab eae eam ean eao eba ebb ebe ebm ebn ebo eea eeb eee eem een eeo em- ema emb eme emm emn emo en- ena enb ene enm enn eno eo- eoa eob eoe eom eon eoo m-o maa mab mae mam man mao mba mbb mbe mbm mbo mea meb mee mem men meo mma mmb mme mmm mmn mmo mna mnb mne mnm mnn mno moa mob moe mom mon moo naa nab nae nam nan nao nba nbb nbe nbm nbn nbo ne- nea neb nee nem nen neo nma nmb nme nmm nmn nmo nna nnb nne nnm nnn nno no- noa nob noe nom non noo oaa oab oae oam oan oao ob- oba obb obe obm obn obo oea oeb oee oem oen oeo om- oma omb ome omm omn omo on- ona onb one onn ono oo- ooa oob oom oon ooo