a-a a-b aaa aab aae aak aan aao aap aas ab- aba abb abe abk abn abo abp abs aea aeb aee aek aen aeo aep aes aka akb ake akk akn ako akp aks an- ana anb ane ank ann ano anp ans aoa aob aoe aok aon aoo aop aos ap- apa apb ape apk apn apo app aps as- asa asb ase ask asn aso asp ass b-p baa bab bae bak ban bao bap bas bba bbb bbe bbk bbn bbo bbp bbs be- bea beb bee bek ben beo bep bes bka bkb bke bkk bkn bko bkp bks bna bnb bne bnk bnn bno bnp bns boa bob boe bok bon boo bop bos bpa bpb bpe bpn bpo bpp bps bsa bsb bse bsk bsn bso bsp bss eaa eab eae eak ean eao eap eas eba ebb ebe ebk ebn ebo ebp ebs eea eeb eee eek een eeo eep ees eka ekb eke eko ekp eks en- ena enb ene enk enn eno enp ens eo- eoa eob eoe eok eon eoo eop eos ep- epa epb epe epn epo epp eps es- esa esb ese esk esn eso esp ess ka- kaa kab kae kak kan kao kap kas kba kbb kbe kbk kbn kbo kbp kbs ke- kea keb kee kek ken keo kep kes kkb kke kkk kkn kkp kks kn- kna kne knk knn kno knp koa kob koe kok kon koo kop kos kpa kpe kpk kpn kpo kpp kps ksa ksb kse ksk ksn kso ksp kss naa nab nae nak nan nao nap nas nba nbb nbe nbk nbn nbo nbp nbs ne- nea neb nee nek nen neo nep nes nka nke nkk nkn nko nkp nks nna nnb nne nnk nnn nno nnp nns no- noa nob noe nok non noo nop nos npa npb npe npn npo npp nps nsa nsb nse nsk nsn nso nsp nss oaa oab oae oak oan oao oap oas ob- oba obb obe obk obn obo obp obs oea oeb oee oen oeo oep oes oka okb oke okk oko okp oks on- ona onb one onk onn ono onp ons oo- ooa oob ook oon ooo oop oos op- opa opb ope opk opn opo opp ops os- osa osb ose osk osn oso osp oss p-p paa pab pae pak pan pao pap pas pba pbb pbe pbk pbn pbo pbp pbs pea peb pee pek pen peo pep pes pka pkb pke pkn pko pkp pks pn- pna pnb pne pnk pnn pno pnp pns poa pob poe pok pon poo pop pos ppa ppb ppe ppk ppn ppo ppp pps ps- psa psb pse psk psn pso psp pss saa sab sae sak san sao sap sas sba sbb sbe sbk sbn sbo sbp sbs se- sea seb see sek sen seo sep ses sk- ska skb ske skk sko skp sks sna snb sne snk snn sno snp sns soa sob soe sok son soo sop sos spa spb spe spk spn spo spp sps ss- ssa ssb sse ssk ssn sso ssp sss