a-a a-b aaa aab aae aah aan aao ab- aba abb abe abh abn abo aea aeb aee aeh aen aeo aha ahb ahe ahh ahn aho an- ana anb ane anh ann ano aoa aob aoe aoh aon aoo baa bab bae bah ban bao bba bbb bbe bbh bbn bbo be- bea beb bee beh ben beo bha bhb bhe bhh bho bna bnb bne bnn bno boa bob boe boh bon boo eaa eab eae eah ean eao eba ebb ebe ebh ebn ebo eea eeb eee een eeo eha ehb ehe ehh ehn eho en- ena enb ene enh enn eno eo- eoa eob eoe eoh eon eoo haa hab hae hah han hao hba hbb hbe hbh hbn hbo he- hea heb hee heh hen heo hha hhb hhe hhh hhn hho hna hnb hne hnh hnn hno hoa hob hoe hoh hon hoo naa nab nae nah nan nao nba nbb nbe nbn nbo ne- nea neb nee neh nen neo nha nhb nhe nhh nhn nna nnb nne nnh nnn nno no- noa nob noe noh non noo oaa oab oae oah oan oao ob- oba obb obe obh obn obo oea oeb oee oeh oen oeo oha ohe ohh ohn oho on- ona onb one onh onn ono oo- ooa oob ooh oon ooo