a-a a-b a-i aaa aab aae aaf aai aan aao ab- aba abb abe abf abi abn abo aea aeb aee aef aei aen aeo af- afa afb afe aff afi afn afo ai- aia aib aie aif aii ain aio an- ana anb ane anf ani ann ano aoa aob aoe aof aoi aon aoo baa bab bae baf bai ban bao bba bbb bbe bbf bbi bbn bbo be- bea beb bee bef bei ben beo bfa bfb bfe bff bfi bfn bfo bi- bia bib bie bif bii bin bio bna bnb bne bnf bni bnn bno boa bob boe bof boi bon boo eaa eab eae eaf eai ean eao eba ebb ebe ebf ebi ebn ebo eea eeb eee eef een eeo ef- efa efb efe eff efi efo eia eib eie eif eii ein eio en- ena enb ene enf eni enn eno eo- eoa eob eoe eof eoi eon eoo faa fab fae faf fai fan fao fba fbb fbe fbf fbi fbn fbo fea feb fee fef fei fen feo ffa ffe fff ffi ffn ffo fia fib fie fif fii fin fna fnb fne fnf fni fnn foa fob foe fof foi fon foo i-f ia- iaa iab iae iaf iai ian iao iba ibb ibe ibf ibi ibn ibo ie- iea iee ief iei ien ifa ifb ife iff ifi ifn ifo iia iib iie iif iii iin iio in- ina inb ine inf ini inn ino io- ioa iob ioe iof ioi ion ioo n-i naa nab nae naf nai nan nao nba nbb nbe nbf nbi nbn nbo ne- nea neb nee nef nei nen neo nfa nfb nfe nff nfi nfn nfo nia nib nie nif nii nin nio nna nnb nne nnf nni nnn nno no- noa nob noe nof noi non noo o-i oaa oab oae oaf oai oan oao ob- oba obb obe obf obi obn obo oea oeb oee oef oei oen oeo of- ofa ofb ofe off ofi ofn ofo oia oib oie oif oii oin oio on- ona onb one onf oni onn ono oo- ooa oob oof ooi oon ooo