a-a a-b a-i aaa aab aae aai aak aao aap aas ab- aba abb abe abi abk abo abp abs aea aeb aee aei aek aeo aep aes ai- aia aib aie aii aik aio aip ais aka akb ake aki akk ako akp aks aoa aob aoe aoi aok aoo aop aos ap- apa apb ape api apk apo app aps as- asa asb ase asi ask aso asp ass b-p baa bab bae bai bak bao bap bas bba bbb bbe bbi bbk bbo bbp bbs be- bea beb bee bei bek beo bep bes bi- bia bib bie bii bik bio bip bis bka bkb bke bkk bko bkp bks boa bob boe boi bok boo bop bos bpa bpb bpe bpi bpo bpp bps bsa bsb bse bsi bsk bso bsp bss eaa eab eae eai eak eao eap eas eba ebb ebe ebi ebk ebo ebp ebs eea eeb eee eek eeo eep ees eia eib eie eii eik eio eip eis eka ekb eke eki eko ekp eks eo- eoa eob eoe eoi eok eoo eop eos ep- epa epb epe epi epo epp eps es- esa esb ese esi esk eso esp ess ia- iaa iab iae iai iao iap ias iba ibb ibe ibi ibk ibo ibp ibs ie- iea iee iei iek iep ies iia iib iie iii iio iip iis ika ikb ike iki ikk iko iks io- ioa iob ioe ioi ioo iop ios ipa ipb ipe ipi ipo ipp ips is- isa isb ise isi isk iso isp iss ka- kaa kab kae kai kak kao kap kas kba kbb kbe kbi kbk kbo kbp kbs ke- kea keb kee kei kek keo kep kes kia kib kie kii kik kio kip kis kkb kke kki kkk kkp kks koa kob koe koi kok koo kop kos kpa kpe kpi kpk kpo kpp kps ksa ksb kse ksi ksk kso ksp kss o-i oaa oab oae oai oak oao oap oas ob- oba obb obe obi obk obo obp obs oea oeb oee oei oeo oep oes oia oib oie oii oik oio oip ois oka okb oke oki okk oko okp oks oo- ooa oob ooi ook ooo oop oos op- opa opb ope opi opk opo opp ops os- osa osb ose osi osk oso osp oss p-p paa pab pae pai pak pao pap pas pba pbb pbe pbi pbk pbo pbp pbs pea peb pee pei pek peo pep pes pia pib pie pii pik pio pip pis pka pkb pke pki pko pkp pks poa pob poe poi pok poo pop pos ppa ppb ppe ppi ppk ppo ppp pps ps- psa psb pse psi psk pso psp pss saa sab sae sai sak sao sap sas sba sbb sbe sbi sbk sbo sbp sbs se- sea seb see sei sek seo sep ses sia sib sie sii sik sio sip sis sk- ska skb ske ski skk sko skp sks soa sob soe soi sok soo sop sos spa spb spe spi spk spo spp sps ss- ssa ssb sse ssi ssk sso ssp sss