-er a-a a-b aaa aab aae aah aak aao aar ab- aba abb abe abh abk abo abr aea aeb aee aeh aek aeo aer aha ahb ahe ahh ahk aho ahr aka akb ake akh akk ako akr aoa aob aoe aoh aok aoo aor ar- ara arb are arh ark aro arr baa bab bae bah bak bao bar bba bbb bbe bbh bbk bbo bbr be- bea beb bee beh bek beo ber bha bhb bhe bhh bhk bho bhr bka bkb bke bkk bko bkr boa bob boe boh bok boo bor bra brb bre brh brk bro brr eaa eab eae eah eak eao ear eba ebb ebe ebh ebk ebo ebr eea eeb eee eek eeo eer eha ehb ehe ehh eho ehr eka ekb eke ekh eko ekr eo- eoa eob eoe eoh eok eoo eor era erb ere erh erk ero err haa hab hae hah hak hao har hba hbb hbe hbh hbk hbo hbr he- hea heb hee heh hek heo her hha hhb hhe hhh hhk hho hhr hka hkb hkh hkk hko hkr hoa hob hoe hoh hok hoo hor hr- hra hrb hre hrh hrk hro hrr ka- kaa kab kae kah kak kao kar kba kbb kbe kbh kbk kbo kbr ke- kea keb kee keh kek keo ker kha khe khh khk kho khr kkb kke kkh kkk kkr koa kob koe koh kok koo kor kra krk kro krr oaa oab oae oah oak oao oar ob- oba obb obe obh obk obo obr oea oeb oee oeh oeo oer oha ohe ohh oho ohr oka okb oke okk oko okr oo- ooa oob ooh ook ooo oor or- ora orb ore orh ork oro orr ra- raa rab rae rah rak rao rar rba rbb rbe rbh rbk rbo rbr re- rea reb ree reh rek reo rer rh- rha rhb rhe rhh rho rhr rkb rke rkk rko roa rob roe roh rok roo ror rra rrb rrh rrk rrr