a-a a-b aaa aab aan aao aar aay ab- aba abb abn abo abr aby an- ana anb ann ano anr any aoa aob aon aoo aor ar- ara arb arn aro arr ary ay- aya ayn ayo ayr baa bab ban bao bar bay bba bbb bbn bbo bbr bby bna bnb bnn bno bnr boa bob bon boo bor boy bra brb brn bro brr bry by- bya byn byo byr naa nab nan nao nar nay nba nbb nbn nbo nbr nna nnb nnn nno no- noa nob non noo nor noy nra nrb nrn nro nrr nry nya nyn nyo nyy oaa oab oan oao oar ob- oba obb obn obo obr oby on- ona onb onn ono onr ony oo- ooa oob oon ooo oor or- ora orb orn oro orr ory oya oyo ra- raa rab ran rao rar ray rba rbb rbn rbo rbr rna rnb rnn rno rnr rny roa rob ron roo ror roy rra rrb rrn rrr ry- rya ryn ryo ryr ryy yaa yab yan yao yar yay ybr yby yna ynn yny yob yon yoo yor yoy yra yrn yro yyb yyy