-er a-a a-b a-i aaa aab aae aag aai aak aan aar ab- aba abb abe abg abi abk abn abr aea aeb aee aeg aei aek aen aer ag- aga agb age agg agi agk agn agr ai- aia aib aie aig aii aik ain air aka akb ake akg aki akk akn akr an- ana anb ane ang ani ank ann anr ar- ara arb are arg ari ark arn arr baa bab bae bag bai bak ban bar bba bbb bbe bbg bbi bbk bbn bbr be- bea beb bee beg bei bek ben ber bga bgb bge bgg bgi bgk bgn bgr bi- bia bib bie big bii bik bin bir bka bkb bke bkg bkk bkn bkr bna bnb bne bng bni bnk bnn bnr bra brb bre brg bri brk brn brr eaa eab eae eag eai eak ean ear eba ebb ebe ebg ebi ebk ebn ebr eea eeb eee eeg eek een eer ega egb ege egg egi egn egr eia eib eie eig eii eik ein eir eka ekb eke ekg eki ekr en- ena enb ene eng eni enk enn enr era erb ere erg eri erk ern err gaa gab gae gag gai gak gan gar gba gbe gbg gbi gbk gbn gbr ge- gea geb gee geg gei gek gen ger gga ggb ggg ggi ggn ggr gia gib gie gig gii gik gin gir gka gkb gkn gna gnb gne gni gnn gnr gra grb gre grg gri grk grn grr ia- iaa iab iae iag iai ian iar iba ibb ibe ibg ibi ibk ibn ibr ie- iea iee ieg iei iek ien ier iga igb ige igg igi igk ign igr iia iib iie iii iin iir ika ikb ike iki ikk ikr in- ina inb ine ing ini ink inn inr ir- ira irb ire irg iri irk irn irr ka- kaa kab kae kag kai kak kan kar kba kbb kbe kbi kbk kbn kbr ke- kea keb kee keg kei kek ken ker kga kgb kgi kia kib kie kig kii kik kin kir kkb kke kki kkk kkn kkr kn- kna kne kng kni knk knn knr kra krg kri krk krn krr n-i naa nab nae nag nai nak nan nar nba nbb nbe nbg nbi nbk nbn nbr ne- nea neb nee neg nei nek nen ner nga ngb nge ngg ngi ngk ngn nia nib nie nig nii nik nin nir nka nke nki nkk nkn nkr nna nnb nne nng nni nnk nnn nra nrb nre nrg nri nrk nrn nrr ra- raa rab rae rag rai rak ran rar rba rbb rbe rbg rbi rbk rbn rbr re- rea reb ree reg rei rek ren rer rga rgb rge rgg rgi rgk rgn rgr ria rib rie rig rii rik rin rir rkb rke rkg rkk rna rnb rng rni rnn rnr rra rrb rrg rri rrk rrn rrr