-er a-a a-b a-q aaa aab aae aak aan aao aaq aar ab- aba abb abe abk abn abo abq abr aea aeb aee aek aen aeo aeq aer aka akb ake akk akn ako akr an- ana anb ane ank ann ano anq anr aoa aob aoe aok aon aoo aor aqa aqn aqo aqr ar- ara arb are ark arn aro arq arr baa bab bae bak ban bao baq bar bba bbb bbe bbk bbn bbo bbq bbr be- bea beb bee bek ben beo beq ber bka bkb bke bkk bkn bko bkq bkr bna bnb bne bnk bnn bno bnr boa bob boe bok bon boo boq bor bqe bra brb bre brk brn bro brq brr eaa eab eae eak ean eao ear eba ebb ebe ebk ebn ebo ebq ebr eea eeb eee eek een eeo eer eka ekb eke eko ekr en- ena enb ene enk enn eno enr eo- eoa eob eoe eok eon eoo eoq eor eqa eqe eqn eqq era erb ere erk ern ero erq err ka- kaa kab kae kak kan kao kar kba kbb kbe kbk kbn kbo kbr ke- kea keb kee kek ken keo ker kkb kke kkk kkn kkr kn- kna kne knk knn kno knr koa kob koe kok kon koo kor kqa kra krk krn kro krr naa nab nae nak nan nao nar nba nbb nbe nbk nbn nbo nbr ne- nea neb nee nek nen neo ner nka nke nkk nkn nko nkr nna nnb nne nnk nnn nno no- noa nob noe nok non noo nor nra nrb nre nrk nrn nro nrr oaa oab oae oak oan oao oaq oar ob- oba obb obe obk obn obo obr oea oeb oee oen oeo oer oka okb oke okk oko okr on- ona onb one onk onn ono onr oo- ooa oob ook oon ooo oor oqb oqo or- ora orb ore ork orn oro orr qaa qan qar qba qbe qbq qee qen qeo qnb qne qnk qoo qor qqk qqq qra qrb qre ra- raa rab rae rak ran rao raq rar rba rbb rbe rbk rbn rbo rbr re- rea reb ree rek ren reo req rer rkb rke rkk rko rna rnb rnn rno rnr roa rob roe rok ron roo ror rqn rra rrb rrk rrn rrq rrr