a-a a-b a-c aaa aab aac aae aak aam aao aas ab- aba abb abc abe abk abm abo abs ac- aca acb acc ace ack acm aco acs aea aeb aec aee aek aem aeo aes aka akb akc ake akk akm ako aks ama amb amc ame amk amm amo ams aoa aob aoc aoe aok aom aoo aos as- asa asb asc ase ask asm aso ass baa bab bac bae bak bam bao bas bba bbb bbc bbe bbk bbm bbo bbs bca bcb bcc bce bck bcm bco bcs be- bea beb bec bee bek bem beo bes bka bkb bkc bke bkk bkm bko bks bma bmb bmc bme bmk bmm bmo bms boa bob boc boe bok bom boo bos bsa bsb bsc bse bsk bsm bso bss c-- caa cab cac cae cak cam cao cas cba cbb cbc cbe cbk cbm cbo cbs cca ccb ccc cce cck ccm cco ccs ce- cea ceb cec cee cek cem ceo ces cka ckb ckc ckm cko cks cma cmb cmc cme cmk cmm cmo cms co- coa cob coc coe cok com coo cos csa csb csc cse csk csm cso css eaa eab eac eae eak eam eao eas eba ebb ebc ebe ebk ebm ebo ebs ec- eca ecb ecc ece eck ecm eco ecs eea eeb eec eee eek eem eeo ees eka ekb ekc eke eko eks em- ema emb emc eme emk emm emo ems eo- eoa eob eoc eoe eok eom eoo eos es- esa esb esc ese esk esm eso ess ka- kaa kab kac kae kak kam kao kas kba kbb kbc kbe kbk kbm kbo kbs kca kcb kcc kce kck kcm kcs ke- kea keb kec kee kek kem keo kes kkb kkc kke kkk kkm kks kma kmb kmc kme kmk kmm kmo kms koa kob koc koe kok kom koo kos ksa ksb ksc kse ksk ksm kso kss m-o maa mab mac mae mak mam mao mas mba mbb mbc mbe mbk mbm mbo mbs mc- mca mcb mcc mce mck mcm mco mcs mea meb mec mee mek mem meo mes mka mkb mkc mke mkk mkm mko mks mma mmb mmc mme mmk mmm mmo mms moa mob moc moe mok mom moo mos msa msb msc mse msk msm mso mss oaa oab oac oae oak oam oao oas ob- oba obb obc obe obk obm obo obs oc- oca ocb occ ock ocm oco ocs oea oeb oec oee oem oeo oes oka okb okc oke okk oko oks om- oma omb omc ome omm omo oms oo- ooa oob ooc ook oom ooo oos os- osa osb osc ose osk osm oso oss saa sab sac sae sak sam sao sas sba sbb sbc sbe sbk sbm sbo sbs sca scb scc sce sck scm sco scs se- sea seb sec see sek sem seo ses sk- ska skb skc ske skk skm sko sks sma smb smc sme smk smm smo sms soa sob soc soe sok som soo sos ss- ssa ssb ssc sse ssk ssm sso sss