a-a a-b aaa aab aae aak aam aao aas ab- aba abb abe abk abm abo abs aea aeb aee aek aem aeo aes aka akb ake akk akm ako aks ama amb ame amk amm amo ams aoa aob aoe aok aom aoo aos as- asa asb ase ask asm aso ass baa bab bae bak bam bao bas bba bbb bbe bbk bbm bbo bbs be- bea beb bee bek bem beo bes bka bkb bke bkk bkm bko bks bma bmb bme bmk bmm bmo bms boa bob boe bok bom boo bos bsa bsb bse bsk bsm bso bss eaa eab eae eak eam eao eas eba ebb ebe ebk ebm ebo ebs eea eeb eee eek eem eeo ees eka ekb eke eko eks em- ema emb eme emk emm emo ems eo- eoa eob eoe eok eom eoo eos es- esa esb ese esk esm eso ess ka- kaa kab kae kak kam kao kas kba kbb kbe kbk kbm kbo kbs ke- kea keb kee kek kem keo kes kkb kke kkk kkm kks kma kmb kme kmk kmm kmo kms koa kob koe kok kom koo kos ksa ksb kse ksk ksm kso kss m-o maa mab mae mak mam mao mas mba mbb mbe mbk mbm mbo mbs mea meb mee mek mem meo mes mka mkb mke mkk mkm mko mks mma mmb mme mmk mmm mmo mms moa mob moe mok mom moo mos msa msb mse msk msm mso mss oaa oab oae oak oam oao oas ob- oba obb obe obk obm obo obs oea oeb oee oem oeo oes oka okb oke okk oko oks om- oma omb ome omm omo oms oo- ooa oob ook oom ooo oos os- osa osb ose osk osm oso oss saa sab sae sak sam sao sas sba sbb sbe sbk sbm sbo sbs se- sea seb see sek sem seo ses sk- ska skb ske skk skm sko sks sma smb sme smk smm smo sms soa sob soe sok som soo sos ss- ssa ssb sse ssk ssm sso sss