a-a a-b aaa aab aad aae aao aas ab- aba abb abd abe abo abs ad- ada adb add ade ado ads aea aeb aed aee aeo aes aoa aob aod aoe aoo aos as- asa asb asd ase aso ass baa bab bad bae bao bas bba bbb bbd bbe bbo bbs bda bdb bdd bde bdo bds be- bea beb bed bee beo bes boa bob bod boe boo bos bsa bsb bsd bse bso bss daa dab dad dae dao das dba dbb dbd dbe dbo dbs dda ddb ddd dde ddo dds de- dea deb ded dee deo des doa dob dod doe doo dos dsa dsb dsd dse dso dss eaa eab ead eae eao eas eba ebb ebd ebe ebo ebs ed- eda edb edd ede edo eds eea eeb eed eee eeo ees eo- eoa eob eod eoe eoo eos es- esa esb esd ese eso ess oaa oab oad oae oao oas ob- oba obb obd obe obo obs oda odb odd ode odo ods oea oeb oed oee oeo oes oo- ooa oob ood ooo oos os- osa osb osd ose oso oss saa sab sad sae sao sas sba sbb sbd sbe sbo sbs sda sdb sdd sde sdo sds se- sea seb sed see seo ses soa sob sod soe soo sos ss- ssa ssb ssd sse sso sss