-er a-a a-b a-i aaa aab aae aai aak aao aap aar aas ab- aba abb abe abi abk abo abp abr abs aea aeb aee aei aek aeo aep aer aes ai- aia aib aie aii aik aio aip air ais aka akb ake aki akk ako akp akr aks aoa aob aoe aoi aok aoo aop aor aos ap- apa apb ape api apk apo app apr aps ar- ara arb are ari ark aro arp arr ars as- asa asb ase asi ask aso asp asr ass b-p baa bab bae bai bak bao bap bar bas bba bbb bbe bbi bbk bbo bbp bbr bbs be- bea beb bee bei bek beo bep ber bes bi- bia bib bie bii bik bio bip bir bis bka bkb bke bkk bko bkp bkr bks boa bob boe boi bok boo bop bor bos bpa bpb bpe bpi bpo bpp bpr bps bra brb bre bri brk bro brp brr brs bsa bsb bse bsi bsk bso bsp bsr bss eaa eab eae eai eak eao eap ear eas eba ebb ebe ebi ebk ebo ebp ebr ebs eea eeb eee eek eeo eep eer ees eia eib eie eii eik eio eip eir eis eka ekb eke eki eko ekp ekr eks eo- eoa eob eoe eoi eok eoo eop eor eos ep- epa epb epe epi epo epp epr eps era erb ere eri erk ero erp err ers es- esa esb ese esi esk eso esp esr ess ia- iaa iab iae iai iao iap iar ias iba ibb ibe ibi ibk ibo ibp ibr ibs ie- iea iee iei iek iep ier ies iia iib iie iii iio iip iir iis ika ikb ike iki ikk iko ikr iks io- ioa iob ioe ioi ioo iop ior ios ipa ipb ipe ipi ipo ipp ipr ips ir- ira irb ire iri irk iro irp irr irs is- isa isb ise isi isk iso isp isr iss ka- kaa kab kae kai kak kao kap kar kas kba kbb kbe kbi kbk kbo kbp kbr kbs ke- kea keb kee kei kek keo kep ker kes kia kib kie kii kik kio kip kir kis kkb kke kki kkk kkp kkr kks koa kob koe koi kok koo kop kor kos kpa kpe kpi kpk kpo kpp kpr kps kra kri krk kro krp krr krs ksa ksb kse ksi ksk kso ksp ksr kss o-i oaa oab oae oai oak oao oap oar oas ob- oba obb obe obi obk obo obp obr obs oea oeb oee oei oeo oep oer oes oia oib oie oii oik oio oip oir ois oka okb oke oki okk oko okp okr oks oo- ooa oob ooi ook ooo oop oor oos op- opa opb ope opi opk opo opp opr ops or- ora orb ore ori ork oro orp orr ors os- osa osb ose osi osk oso osp osr oss p-p paa pab pae pai pak pao pap par pas pba pbb pbe pbi pbk pbo pbp pbr pbs pea peb pee pei pek peo pep per pes pia pib pie pii pik pio pip pir pis pka pkb pke pki pko pkp pkr pks poa pob poe poi pok poo pop por pos ppa ppb ppe ppi ppk ppo ppp ppr pps pra prb pre pri prk pro prp prr prs ps- psa psb pse psi psk pso psp psr pss ra- raa rab rae rai rak rao rap rar ras rba rbb rbe rbi rbk rbo rbp rbr rbs re- rea reb ree rei rek reo rep rer res ria rib rie rii rik rio rip rir ris rkb rke rkk rko rkp rks roa rob roe roi rok roo rop ror ros rpa rpb rpe rpi rpk rpo rpp rpr rps rra rrb rri rrk rrp rrr rrs rsa rsb rse rsi rsk rso rsp rsr rss saa sab sae sai sak sao sap sar sas sba sbb sbe sbi sbk sbo sbp sbr sbs se- sea seb see sei sek seo sep ser ses sia sib sie sii sik sio sip sir sis sk- ska skb ske ski skk sko skp skr sks soa sob soe soi sok soo sop sor sos spa spb spe spi spk spo spp spr sps sr- sra srb sre sri srk sro srp srr srs ss- ssa ssb sse ssi ssk sso ssp ssr sss