-er a-a a-b a-i aaa aab aae aai aak aan aao aar ab- aba abb abe abi abk abn abo abr aea aeb aee aei aek aen aeo aer ai- aia aib aie aii aik ain aio air aka akb ake aki akk akn ako akr an- ana anb ane ani ank ann ano anr aoa aob aoe aoi aok aon aoo aor ar- ara arb are ari ark arn aro arr baa bab bae bai bak ban bao bar bba bbb bbe bbi bbk bbn bbo bbr be- bea beb bee bei bek ben beo ber bi- bia bib bie bii bik bin bio bir bka bkb bke bkk bkn bko bkr bna bnb bne bni bnk bnn bno bnr boa bob boe boi bok bon boo bor bra brb bre bri brk brn bro brr eaa eab eae eai eak ean eao ear eba ebb ebe ebi ebk ebn ebo ebr eea eeb eee eek een eeo eer eia eib eie eii eik ein eio eir eka ekb eke eki eko ekr en- ena enb ene eni enk enn eno enr eo- eoa eob eoe eoi eok eon eoo eor era erb ere eri erk ern ero err ia- iaa iab iae iai ian iao iar iba ibb ibe ibi ibk ibn ibo ibr ie- iea iee iei iek ien ier iia iib iie iii iin iio iir ika ikb ike iki ikk iko ikr in- ina inb ine ini ink inn ino inr io- ioa iob ioe ioi ion ioo ior ir- ira irb ire iri irk irn iro irr ka- kaa kab kae kai kak kan kao kar kba kbb kbe kbi kbk kbn kbo kbr ke- kea keb kee kei kek ken keo ker kia kib kie kii kik kin kio kir kkb kke kki kkk kkn kkr kn- kna kne kni knk knn kno knr koa kob koe koi kok kon koo kor kra kri krk krn kro krr n-i naa nab nae nai nak nan nao nar nba nbb nbe nbi nbk nbn nbo nbr ne- nea neb nee nei nek nen neo ner nia nib nie nii nik nin nio nir nka nke nki nkk nkn nko nkr nna nnb nne nni nnk nnn nno no- noa nob noe noi nok non noo nor nra nrb nre nri nrk nrn nro nrr o-i oaa oab oae oai oak oan oao oar ob- oba obb obe obi obk obn obo obr oea oeb oee oei oen oeo oer oia oib oie oii oik oin oio oir oka okb oke oki okk oko okr on- ona onb one oni onk onn ono onr oo- ooa oob ooi ook oon ooo oor or- ora orb ore ori ork orn oro orr ra- raa rab rae rai rak ran rao rar rba rbb rbe rbi rbk rbn rbo rbr re- rea reb ree rei rek ren reo rer ria rib rie rii rik rin rio rir rkb rke rkk rko rna rnb rni rnn rno rnr roa rob roe roi rok ron roo ror rra rrb rri rrk rrn rrr