a-a a-b a-i aaa aab aai aak aan aao aap aar aas ab- aba abb abi abk abn abo abp abr abs ai- aia aib aii aik ain aio aip air ais aka akb aki akk akn ako akp akr aks an- ana anb ani ank ann ano anp anr ans aoa aob aoi aok aon aoo aop aor aos ap- apa apb api apk apn apo app apr aps ar- ara arb ari ark arn aro arp arr ars as- asa asb asi ask asn aso asp asr ass b-p baa bab bai bak ban bao bap bar bas bba bbb bbi bbk bbn bbo bbp bbr bbs bi- bia bib bii bik bin bio bip bir bis bka bkb bkk bkn bko bkp bkr bks bna bnb bni bnk bnn bno bnp bnr bns boa bob boi bok bon boo bop bor bos bpa bpb bpi bpn bpo bpp bpr bps bra brb bri brk brn bro brp brr brs bsa bsb bsi bsk bsn bso bsp bsr bss ia- iaa iab iai ian iao iap iar ias iba ibb ibi ibk ibn ibo ibp ibr ibs iia iib iii iin iio iip iir iis ika ikb iki ikk iko ikr iks in- ina inb ini ink inn ino inp inr ins io- ioa iob ioi ion ioo iop ior ios ipa ipb ipi ipn ipo ipp ipr ips ir- ira irb iri irk irn iro irp irr irs is- isa isb isi isk isn iso isp isr iss ka- kaa kab kai kak kan kao kap kar kas kba kbb kbi kbk kbn kbo kbp kbr kbs kia kib kii kik kin kio kip kir kis kkb kki kkk kkn kkp kkr kks kn- kna kni knk knn kno knp knr koa kob koi kok kon koo kop kor kos kpa kpi kpk kpn kpo kpp kpr kps kra kri krk krn kro krp krr krs ksa ksb ksi ksk ksn kso ksp ksr kss n-i naa nab nai nak nan nao nap nar nas nba nbb nbi nbk nbn nbo nbp nbr nbs nia nib nii nik nin nio nip nir nis nka nki nkk nkn nko nkp nkr nks nna nnb nni nnk nnn nno nnp nns no- noa nob noi nok non noo nop nor nos npa npb npi npn npo npp npr nps nra nrb nri nrk nrn nro nrp nrr nrs nsa nsb nsi nsk nsn nso nsp nsr nss o-i oaa oab oai oak oan oao oap oar oas ob- oba obb obi obk obn obo obp obr obs oia oib oii oik oin oio oip oir ois oka okb oki okk oko okp okr oks on- ona onb oni onk onn ono onp onr ons oo- ooa oob ooi ook oon ooo oop oor oos op- opa opb opi opk opn opo opp opr ops or- ora orb ori ork orn oro orp orr ors os- osa osb osi osk osn oso osp osr oss p-p paa pab pai pak pan pao pap par pas pba pbb pbi pbk pbn pbo pbp pbr pbs pia pib pii pik pin pio pip pir pis pka pkb pki pkn pko pkp pkr pks pn- pna pnb pni pnk pnn pno pnp pnr pns poa pob poi pok pon poo pop por pos ppa ppb ppi ppk ppn ppo ppp ppr pps pra prb pri prk prn pro prp prr prs ps- psa psb psi psk psn pso psp psr pss ra- raa rab rai rak ran rao rap rar ras rba rbb rbi rbk rbn rbo rbp rbr rbs ria rib rii rik rin rio rip rir ris rkb rkk rko rkp rks rna rnb rni rnn rno rnp rnr rns roa rob roi rok ron roo rop ror ros rpa rpb rpi rpk rpn rpo rpp rpr rps rra rrb rri rrk rrn rrp rrr rrs rsa rsb rsi rsk rsn rso rsp rsr rss saa sab sai sak san sao sap sar sas sba sbb sbi sbk sbn sbo sbp sbr sbs sia sib sii sik sin sio sip sir sis sk- ska skb ski skk sko skp skr sks sna snb sni snk snn sno snp snr sns soa sob soi sok son soo sop sor sos spa spb spi spk spn spo spp spr sps sr- sra srb sri srk srn sro srp srr srs ss- ssa ssb ssi ssk ssn sso ssp ssr sss