a-a a-b aaa aab aaf aan aao aar aay ab- aba abb abf abn abo abr aby af- afa afb aff afn afo afr afy an- ana anb anf ann ano anr any aoa aob aof aon aoo aor ar- ara arb arf arn aro arr ary ay- aya ayf ayn ayo ayr baa bab baf ban bao bar bay bba bbb bbf bbn bbo bbr bby bfa bfb bff bfn bfo bfr bfy bna bnb bnf bnn bno bnr boa bob bof bon boo bor boy bra brb brf brn bro brr bry by- bya byf byn byo byr faa fab faf fan fao far fay fba fbb fbf fbn fbo fbr ffa fff ffn ffo ffr ffy fna fnb fnf fnn fnr foa fob fof fon foo for foy fra frb frf frn fro frr fry fy- fya fyb fyn fyo naa nab naf nan nao nar nay nba nbb nbf nbn nbo nbr nfa nfb nff nfn nfo nfr nna nnb nnf nnn nno no- noa nob nof non noo nor noy nra nrb nrf nrn nro nrr nry nya nyf nyn nyo nyy oaa oab oaf oan oao oar ob- oba obb obf obn obo obr oby of- ofa ofb off ofn ofo ofr on- ona onb onf onn ono onr ony oo- ooa oob oof oon ooo oor or- ora orb orf orn oro orr ory oya oyo ra- raa rab raf ran rao rar ray rba rbb rbf rbn rbo rbr rfa rfb rff rfn rfo rfr rna rnb rnn rno rnr rny roa rob rof ron roo ror roy rra rrb rrf rrn rrr ry- rya ryf ryn ryo ryr ryy yaa yab yaf yan yao yar yay ybf ybr yby yfa yff yfr yna ynn yny yob yof yon yoo yor yoy yra yrf yrn yro yyb yyf yyy