-er a-a a-b a-z aaa aab aae aak aao aar aaz ab- aba abb abe abk abo abr abz aea aeb aee aek aeo aer aez aka akb ake akk ako akr aoa aob aoe aok aoo aor ar- ara arb are ark aro arr arz az- aza azb aze azo azz baa bab bae bak bao bar baz bba bbb bbe bbk bbo bbr be- bea beb bee bek beo ber bez bka bkb bke bkk bko bkr boa bob boe bok boo bor boz bra brb bre brk bro brr brz bza bze bzo bzr bzz eaa eab eae eak eao ear eaz eba ebb ebe ebk ebo ebr eea eeb eee eek eeo eer eka ekb eke eko ekr eo- eoa eob eoe eok eoo eor era erb ere erk ero err erz eze ezo ezr ezz k-z ka- kaa kab kae kak kao kar kaz kba kbb kbe kbk kbo kbr kbz ke- kea keb kee kek keo ker kez kkb kke kkk kkr koa kob koe kok koo kor koz kra krk kro krr kzo oaa oab oae oak oao oar ob- oba obb obe obk obo obr oea oeb oee oeo oer oka okb oke okk oko okr oo- ooa oob ook ooo oor or- ora orb ore ork oro orr orz oza oze ozo ozz ra- raa rab rae rak rao rar raz rba rbb rbe rbk rbo rbr re- rea reb ree rek reo rer rez rkb rke rkk rko rkz roa rob roe rok roo ror roz rra rrb rrk rrr rza rzb rze rzo zaa zab zak zao zar zaz zbb zbr zea zeb zee zek zeo zer zez zka zo- zoa zob zoe zok zoo zor zro zzr zzz