a-a a-b a-c aaa aab aac aae aak aam aao ab- aba abb abc abe abk abm abo ac- aca acb acc ace ack acm aco aea aeb aec aee aek aem aeo aka akb akc ake akk akm ako ama amb amc ame amk amm amo aoa aob aoc aoe aok aom aoo baa bab bac bae bak bam bao bba bbb bbc bbe bbk bbm bbo bca bcb bcc bce bck bcm bco be- bea beb bec bee bek bem beo bka bkb bkc bke bkk bkm bko bma bmb bmc bme bmk bmm bmo boa bob boc boe bok bom boo c-- caa cab cac cae cak cam cao cba cbb cbc cbe cbk cbm cbo cca ccb ccc cce cck ccm cco ce- cea ceb cec cee cek cem ceo cka ckb ckc ckm cko cma cmb cmc cme cmk cmm cmo co- coa cob coc coe cok com coo eaa eab eac eae eak eam eao eba ebb ebc ebe ebk ebm ebo ec- eca ecb ecc ece eck ecm eco eea eeb eec eee eek eem eeo eka ekb ekc eke eko em- ema emb emc eme emk emm emo eo- eoa eob eoc eoe eok eom eoo ka- kaa kab kac kae kak kam kao kba kbb kbc kbe kbk kbm kbo kca kcb kcc kce kck kcm ke- kea keb kec kee kek kem keo kkb kkc kke kkk kkm kma kmb kmc kme kmk kmm kmo koa kob koc koe kok kom koo m-o maa mab mac mae mak mam mao mba mbb mbc mbe mbk mbm mbo mc- mca mcb mcc mce mck mcm mco mea meb mec mee mek mem meo mka mkb mkc mke mkk mkm mko mma mmb mmc mme mmk mmm mmo moa mob moc moe mok mom moo oaa oab oac oae oak oam oao ob- oba obb obc obe obk obm obo oc- oca ocb occ ock ocm oco oea oeb oec oee oem oeo oka okb okc oke okk oko om- oma omb omc ome omm omo oo- ooa oob ooc ook oom ooo