-er a-a a-b aaa aab aae aah aan aao aar ab- aba abb abe abh abn abo abr aea aeb aee aeh aen aeo aer aha ahb ahe ahh ahn aho ahr an- ana anb ane anh ann ano anr aoa aob aoe aoh aon aoo aor ar- ara arb are arh arn aro arr baa bab bae bah ban bao bar bba bbb bbe bbh bbn bbo bbr be- bea beb bee beh ben beo ber bha bhb bhe bhh bho bhr bna bnb bne bnn bno bnr boa bob boe boh bon boo bor bra brb bre brh brn bro brr eaa eab eae eah ean eao ear eba ebb ebe ebh ebn ebo ebr eea eeb eee een eeo eer eha ehb ehe ehh ehn eho ehr en- ena enb ene enh enn eno enr eo- eoa eob eoe eoh eon eoo eor era erb ere erh ern ero err haa hab hae hah han hao har hba hbb hbe hbh hbn hbo hbr he- hea heb hee heh hen heo her hha hhb hhe hhh hhn hho hhr hna hnb hne hnh hnn hno hoa hob hoe hoh hon hoo hor hr- hra hrb hre hrh hrn hro hrr naa nab nae nah nan nao nar nba nbb nbe nbn nbo nbr ne- nea neb nee neh nen neo ner nha nhb nhe nhh nhn nhr nna nnb nne nnh nnn nno no- noa nob noe noh non noo nor nra nrb nre nrn nro nrr oaa oab oae oah oan oao oar ob- oba obb obe obh obn obo obr oea oeb oee oeh oen oeo oer oha ohe ohh ohn oho ohr on- ona onb one onh onn ono onr oo- ooa oob ooh oon ooo oor or- ora orb ore orh orn oro orr ra- raa rab rae rah ran rao rar rba rbb rbe rbh rbn rbo rbr re- rea reb ree reh ren reo rer rh- rha rhb rhe rhh rhn rho rhr rna rnb rnh rnn rno rnr roa rob roe roh ron roo ror rra rrb rrh rrn rrr