a-a a-b aaa aab aan aao aap aar aas ab- aba abb abn abo abp abr abs an- ana anb ann ano anp anr ans aoa aob aon aoo aop aor aos ap- apa apb apn apo app apr aps ar- ara arb arn aro arp arr ars as- asa asb asn aso asp asr ass b-p baa bab ban bao bap bar bas bba bbb bbn bbo bbp bbr bbs bna bnb bnn bno bnp bnr bns boa bob bon boo bop bor bos bpa bpb bpn bpo bpp bpr bps bra brb brn bro brp brr brs bsa bsb bsn bso bsp bsr bss naa nab nan nao nap nar nas nba nbb nbn nbo nbp nbr nbs nna nnb nnn nno nnp nns no- noa nob non noo nop nor nos npa npb npn npo npp npr nps nra nrb nrn nro nrp nrr nrs nsa nsb nsn nso nsp nsr nss oaa oab oan oao oap oar oas ob- oba obb obn obo obp obr obs on- ona onb onn ono onp onr ons oo- ooa oob oon ooo oop oor oos op- opa opb opn opo opp opr ops or- ora orb orn oro orp orr ors os- osa osb osn oso osp osr oss p-p paa pab pan pao pap par pas pba pbb pbn pbo pbp pbr pbs pn- pna pnb pnn pno pnp pnr pns poa pob pon poo pop por pos ppa ppb ppn ppo ppp ppr pps pra prb prn pro prp prr prs ps- psa psb psn pso psp psr pss ra- raa rab ran rao rap rar ras rba rbb rbn rbo rbp rbr rbs rna rnb rnn rno rnp rnr rns roa rob ron roo rop ror ros rpa rpb rpn rpo rpp rpr rps rra rrb rrn rrp rrr rrs rsa rsb rsn rso rsp rsr rss saa sab san sao sap sar sas sba sbb sbn sbo sbp sbr sbs sna snb snn sno snp snr sns soa sob son soo sop sor sos spa spb spn spo spp spr sps sr- sra srb srn sro srp srr srs ss- ssa ssb ssn sso ssp ssr sss