-er a-a a-b a-i aaa aab aae aai aan aao aar ab- aba abb abe abi abn abo abr aea aeb aee aei aen aeo aer ai- aia aib aie aii ain aio air an- ana anb ane ani ann ano anr aoa aob aoe aoi aon aoo aor ar- ara arb are ari arn aro arr baa bab bae bai ban bao bar bba bbb bbe bbi bbn bbo bbr be- bea beb bee bei ben beo ber bi- bia bib bie bii bin bio bir bna bnb bne bni bnn bno bnr boa bob boe boi bon boo bor bra brb bre bri brn bro brr eaa eab eae eai ean eao ear eba ebb ebe ebi ebn ebo ebr eea eeb eee een eeo eer eia eib eie eii ein eio eir en- ena enb ene eni enn eno enr eo- eoa eob eoe eoi eon eoo eor era erb ere eri ern ero err ia- iaa iab iae iai ian iao iar iba ibb ibe ibi ibn ibo ibr ie- iea iee iei ien ier iia iib iie iii iin iio iir in- ina inb ine ini inn ino inr io- ioa iob ioe ioi ion ioo ior ir- ira irb ire iri irn iro irr n-i naa nab nae nai nan nao nar nba nbb nbe nbi nbn nbo nbr ne- nea neb nee nei nen neo ner nia nib nie nii nin nio nir nna nnb nne nni nnn nno no- noa nob noe noi non noo nor nra nrb nre nri nrn nro nrr o-i oaa oab oae oai oan oao oar ob- oba obb obe obi obn obo obr oea oeb oee oei oen oeo oer oia oib oie oii oin oio oir on- ona onb one oni onn ono onr oo- ooa oob ooi oon ooo oor or- ora orb ore ori orn oro orr ra- raa rab rae rai ran rao rar rba rbb rbe rbi rbn rbo rbr re- rea reb ree rei ren reo rer ria rib rie rii rin rio rir rna rnb rni rnn rno rnr roa rob roe roi ron roo ror rra rrb rri rrn rrr