a-a a-b aaa aab aae aam aao aas ab- aba abb abe abm abo abs aea aeb aee aem aeo aes ama amb ame amm amo ams aoa aob aoe aom aoo aos as- asa asb ase asm aso ass baa bab bae bam bao bas bba bbb bbe bbm bbo bbs be- bea beb bee bem beo bes bma bmb bme bmm bmo bms boa bob boe bom boo bos bsa bsb bse bsm bso bss eaa eab eae eam eao eas eba ebb ebe ebm ebo ebs eea eeb eee eem eeo ees em- ema emb eme emm emo ems eo- eoa eob eoe eom eoo eos es- esa esb ese esm eso ess m-o maa mab mae mam mao mas mba mbb mbe mbm mbo mbs mea meb mee mem meo mes mma mmb mme mmm mmo mms moa mob moe mom moo mos msa msb mse msm mso mss oaa oab oae oam oao oas ob- oba obb obe obm obo obs oea oeb oee oem oeo oes om- oma omb ome omm omo oms oo- ooa oob oom ooo oos os- osa osb ose osm oso oss saa sab sae sam sao sas sba sbb sbe sbm sbo sbs se- sea seb see sem seo ses sma smb sme smm smo sms soa sob soe som soo sos ss- ssa ssb sse ssm sso sss