a-a a-b aaa aab aan aao aar aax aay ab- aba abb abn abo abr abx aby an- ana anb ann ano anr anx any aoa aob aon aoo aor aox ar- ara arb arn aro arr arx ary ax- axa axn axo axr axx ay- aya ayn ayo ayr ayx baa bab ban bao bar bax bay bba bbb bbn bbo bbr bbx bby bna bnb bnn bno bnr bnx boa bob bon boo bor box boy bra brb brn bro brr brx bry bxb bxn bxo bxx by- bya byn byo byr naa nab nan nao nar nax nay nba nbb nbn nbo nbr nbx nna nnb nnn nno no- noa nob non noo nor nox noy nra nrb nrn nro nrr nrx nry nya nyn nyo nyx nyy oaa oab oan oao oar oax ob- oba obb obn obo obr obx oby on- ona onb onn ono onr onx ony oo- ooa oob oon ooo oor oox or- ora orb orn oro orr orx ory ox- oxa oxb oxn oxo oxx oxy oya oyo ra- raa rab ran rao rar rax ray rba rbb rbn rbo rbr rbx rna rnb rnn rno rnr rny roa rob ron roo ror rox roy rra rrb rrn rrr rxr ry- rya ryn ryo ryr ryy xaa xan xar xbr xbx xna xno xoa xon xoo xor xox xrx xry xxo xxx xxy xyr xyy yaa yab yan yao yar yax yay ybr yby yna ynn yny yob yon yoo yor yox yoy yra yrn yro yxa yxy yyb yyy