bbb bbc bbe bbk bbm bbo bcb bcc bce bck bcm bco be- beb bec bee bek bem beo bkb bkc bke bkk bkm bko bmb bmc bme bmk bmm bmo bob boc boe bok bom boo c-- cbb cbc cbe cbk cbm cbo ccb ccc cce cck ccm cco ce- ceb cec cee cek cem ceo ckb ckc ckm cko cmb cmc cme cmk cmm cmo co- cob coc coe cok com coo ebb ebc ebe ebk ebm ebo ec- ecb ecc ece eck ecm eco eeb eec eee eek eem eeo ekb ekc eke eko em- emb emc eme emk emm emo eo- eob eoc eoe eok eom eoo kbb kbc kbe kbk kbm kbo kcb kcc kce kck kcm ke- keb kec kee kek kem keo kkb kkc kke kkk kkm kmb kmc kme kmk kmm kmo kob koc koe kok kom koo m-o mbb mbc mbe mbk mbm mbo mc- mcb mcc mce mck mcm mco meb mec mee mek mem meo mkb mkc mke mkk mkm mko mmb mmc mme mmk mmm mmo mob moc moe mok mom moo ob- obb obc obe obk obm obo oc- ocb occ ock ocm oco oeb oec oee oem oeo okb okc oke okk oko om- omb omc ome omm omo oo- oob ooc ook oom ooo