-er a-a a-b aaa aab aae aaf aak aan aao aap aar ab- aba abb abe abf abk abn abo abp abr aea aeb aee aef aek aen aeo aep aer af- afa afb afe aff afk afn afo afp afr aka akb ake akk akn ako akp akr an- ana anb ane anf ank ann ano anp anr aoa aob aoe aof aok aon aoo aop aor ap- apa apb ape apf apk apn apo app apr ar- ara arb are arf ark arn aro arp arr b-p baa bab bae baf bak ban bao bap bar bba bbb bbe bbf bbk bbn bbo bbp bbr be- bea beb bee bef bek ben beo bep ber bfa bfb bfe bff bfn bfo bfp bfr bka bkb bke bkf bkk bkn bko bkp bkr bna bnb bne bnf bnk bnn bno bnp bnr boa bob boe bof bok bon boo bop bor bpa bpb bpe bpf bpn bpo bpp bpr bra brb bre brf brk brn bro brp brr eaa eab eae eaf eak ean eao eap ear eba ebb ebe ebf ebk ebn ebo ebp ebr eea eeb eee eef eek een eeo eep eer ef- efa efb efe eff efo efp efr eka ekb eke ekf eko ekp ekr en- ena enb ene enf enk enn eno enp enr eo- eoa eob eoe eof eok eon eoo eop eor ep- epa epb epe epf epn epo epp epr era erb ere erf erk ern ero erp err faa fab fae faf fak fan fao fap far fba fbb fbe fbf fbk fbn fbo fbp fbr fea feb fee fef fek fen feo fep fer ffa ffe fff ffk ffn ffo ffp ffr fka fkb fkf fkk fkp fna fnb fne fnf fnk fnn fnp fnr foa fob foe fof fok fon foo fop for fpa fpb fpe fpk fpn fpo fpp fpr fra frb fre frf frk frn fro frp frr ka- kaa kab kae kaf kak kan kao kap kar kba kbb kbe kbf kbk kbn kbo kbp kbr ke- kea keb kee kef kek ken keo kep ker kfa kff kfo kkb kke kkk kkn kkp kkr kn- kna kne knf knk knn kno knp knr koa kob koe kof kok kon koo kop kor kpa kpe kpf kpk kpn kpo kpp kpr kra krf krk krn kro krp krr naa nab nae naf nak nan nao nap nar nba nbb nbe nbf nbk nbn nbo nbp nbr ne- nea neb nee nef nek nen neo nep ner nfa nfb nfe nff nfk nfn nfo nfp nfr nka nke nkf nkk nkn nko nkp nkr nna nnb nne nnf nnk nnn nno nnp no- noa nob noe nof nok non noo nop nor npa npb npe npf npn npo npp npr nra nrb nre nrf nrk nrn nro nrp nrr oaa oab oae oaf oak oan oao oap oar ob- oba obb obe obf obk obn obo obp obr oea oeb oee oef oen oeo oep oer of- ofa ofb ofe off ofn ofo ofp ofr oka okb oke okk oko okp okr on- ona onb one onf onk onn ono onp onr oo- ooa oob oof ook oon ooo oop oor op- opa opb ope opf opk opn opo opp opr or- ora orb ore orf ork orn oro orp orr p-p paa pab pae paf pak pan pao pap par pba pbb pbe pbf pbk pbn pbo pbp pbr pea peb pee pef pek pen peo pep per pfa pfb pfe pff pfk pfn pfo pfp pfr pka pkb pke pkf pkn pko pkp pkr pn- pna pnb pne pnf pnk pnn pno pnp pnr poa pob poe pof pok pon poo pop por ppa ppb ppe ppf ppk ppn ppo ppp ppr pra prb pre prf prk prn pro prp prr ra- raa rab rae raf rak ran rao rap rar rba rbb rbe rbf rbk rbn rbo rbp rbr re- rea reb ree ref rek ren reo rep rer rfa rfb rfe rff rfk rfn rfo rfp rfr rkb rke rkf rkk rko rkp rna rnb rnn rno rnp rnr roa rob roe rof rok ron roo rop ror rpa rpb rpe rpf rpk rpn rpo rpp rpr rra rrb rrf rrk rrn rrp rrr