a-a a-b a-i aaa aab aaf aag aai aan aao aar ab- aba abb abf abg abi abn abo abr af- afa afb aff afg afi afn afo afr ag- aga agb agf agg agi agn ago agr ai- aia aib aif aig aii ain aio air an- ana anb anf ang ani ann ano anr aoa aob aof aog aoi aon aoo aor ar- ara arb arf arg ari arn aro arr baa bab baf bag bai ban bao bar bba bbb bbf bbg bbi bbn bbo bbr bfa bfb bff bfg bfi bfn bfo bfr bga bgb bgf bgg bgi bgn bgo bgr bi- bia bib bif big bii bin bio bir bna bnb bnf bng bni bnn bno bnr boa bob bof bog boi bon boo bor bra brb brf brg bri brn bro brr faa fab faf fag fai fan fao far fba fbb fbf fbg fbi fbn fbo fbr ffa fff ffg ffi ffn ffo ffr fga fgb fgf fgg fgi fgn fgr fia fib fif fig fii fin fir fna fnb fnf fng fni fnn fnr foa fob fof fog foi fon foo for fra frb frf frg fri frn fro frr gaa gab gaf gag gai gan gao gar gba gbf gbg gbi gbn gbo gbr gfa gfb gff gfi gfo gfr gga ggb ggg ggi ggn ggo ggr gia gib gif gig gii gin gio gir gna gnb gnf gni gnn gno gnr goa gob gof gog goi gon goo gor gra grb grf grg gri grn gro grr i-f ia- iaa iab iaf iag iai ian iao iar iba ibb ibf ibg ibi ibn ibo ibr ifa ifb iff ifg ifi ifn ifo ifr iga igb igf igg igi ign igo igr iia iib iif iii iin iio iir in- ina inb inf ing ini inn ino inr io- ioa iob iof iog ioi ion ioo ior ir- ira irb irf irg iri irn iro irr n-i naa nab naf nag nai nan nao nar nba nbb nbf nbg nbi nbn nbo nbr nfa nfb nff nfi nfn nfo nfr nga ngb ngf ngg ngi ngn ngo nia nib nif nig nii nin nio nir nna nnb nnf nng nni nnn nno no- noa nob nof nog noi non noo nor nra nrb nrf nrg nri nrn nro nrr o-i oaa oab oaf oag oai oan oao oar ob- oba obb obf obg obi obn obo obr of- ofa ofb off ofg ofi ofn ofo ofr oga ogf ogg ogi ogn ogo oia oib oif oii oin oio oir on- ona onb onf ong oni onn ono onr oo- ooa oob oof oog ooi oon ooo oor or- ora orb orf org ori orn oro orr ra- raa rab raf rag rai ran rao rar rba rbb rbf rbg rbi rbn rbo rbr rfa rfb rff rfg rfi rfn rfo rfr rga rgb rgf rgg rgi rgn rgo rgr ria rib rif rig rii rin rio rir rna rnb rng rni rnn rno rnr roa rob rof rog roi ron roo ror rra rrb rrf rrg rri rrn rrr