-er a-a a-b aaa aab aae aag aan aao aar ab- aba abb abe abg abn abo abr aea aeb aee aeg aen aeo aer ag- aga agb age agg agn ago agr an- ana anb ane ang ann ano anr aoa aob aoe aog aon aoo aor ar- ara arb are arg arn aro arr baa bab bae bag ban bao bar bba bbb bbe bbg bbn bbo bbr be- bea beb bee beg ben beo ber bga bgb bge bgg bgn bgo bgr bna bnb bne bng bnn bno bnr boa bob boe bog bon boo bor bra brb bre brg brn bro brr eaa eab eae eag ean eao ear eba ebb ebe ebg ebn ebo ebr eea eeb eee eeg een eeo eer ega egb ege egg egn ego egr en- ena enb ene eng enn eno enr eo- eoa eob eoe eog eon eoo eor era erb ere erg ern ero err gaa gab gae gag gan gao gar gba gbe gbg gbn gbo gbr ge- gea geb gee geg gen geo ger gga ggb ggg ggn ggo ggr gna gnb gne gnn gno gnr goa gob goe gog gon goo gor gra grb gre grg grn gro grr naa nab nae nag nan nao nar nba nbb nbe nbg nbn nbo nbr ne- nea neb nee neg nen neo ner nga ngb nge ngg ngn ngo nna nnb nne nng nnn nno no- noa nob noe nog non noo nor nra nrb nre nrg nrn nro nrr oaa oab oae oag oan oao oar ob- oba obb obe obg obn obo obr oea oeb oee oeg oen oeo oer oga oge ogg ogn ogo on- ona onb one ong onn ono onr oo- ooa oob oog oon ooo oor or- ora orb ore org orn oro orr ra- raa rab rae rag ran rao rar rba rbb rbe rbg rbn rbo rbr re- rea reb ree reg ren reo rer rga rgb rge rgg rgn rgo rgr rna rnb rng rnn rno rnr roa rob roe rog ron roo ror rra rrb rrg rrn rrr