-er a-a a-b a-i aaa aab aae aai aak aan aar ab- aba abb abe abi abk abn abr aea aeb aee aei aek aen aer ai- aia aib aie aii aik ain air aka akb ake aki akk akn akr an- ana anb ane ani ank ann anr ar- ara arb are ari ark arn arr baa bab bae bai bak ban bar bba bbb bbe bbi bbk bbn bbr be- bea beb bee bei bek ben ber bi- bia bib bie bii bik bin bir bka bkb bke bkk bkn bkr bna bnb bne bni bnk bnn bnr bra brb bre bri brk brn brr eaa eab eae eai eak ean ear eba ebb ebe ebi ebk ebn ebr eea eeb eee eek een eer eia eib eie eii eik ein eir eka ekb eke eki ekr en- ena enb ene eni enk enn enr era erb ere eri erk ern err ia- iaa iab iae iai ian iar iba ibb ibe ibi ibk ibn ibr ie- iea iee iei iek ien ier iia iib iie iii iin iir ika ikb ike iki ikk ikr in- ina inb ine ini ink inn inr ir- ira irb ire iri irk irn irr ka- kaa kab kae kai kak kan kar kba kbb kbe kbi kbk kbn kbr ke- kea keb kee kei kek ken ker kia kib kie kii kik kin kir kkb kke kki kkk kkn kkr kn- kna kne kni knk knn knr kra kri krk krn krr n-i naa nab nae nai nak nan nar nba nbb nbe nbi nbk nbn nbr ne- nea neb nee nei nek nen ner nia nib nie nii nik nin nir nka nke nki nkk nkn nkr nna nnb nne nni nnk nnn nra nrb nre nri nrk nrn nrr ra- raa rab rae rai rak ran rar rba rbb rbe rbi rbk rbn rbr re- rea reb ree rei rek ren rer ria rib rie rii rik rin rir rkb rke rkk rna rnb rni rnn rnr rra rrb rri rrk rrn rrr