a-a a-b aaa aab aad aan aao aas ab- aba abb abd abn abo abs ad- ada adb add adn ado ads an- ana anb and ann ano ans aoa aob aod aon aoo aos as- asa asb asd asn aso ass baa bab bad ban bao bas bba bbb bbd bbn bbo bbs bda bdb bdd bdo bds bna bnb bnd bnn bno bns boa bob bod bon boo bos bsa bsb bsd bsn bso bss daa dab dad dan dao das dba dbb dbd dbn dbo dbs dda ddb ddd ddn ddo dds dna dnb dnd dnn dno dns doa dob dod don doo dos dsa dsb dsd dsn dso dss naa nab nad nan nao nas nba nbb nbd nbn nbo nbs nda ndb ndd ndn ndo nds nna nnb nnn nno nns no- noa nob nod non noo nos nsa nsb nsd nsn nso nss oaa oab oad oan oao oas ob- oba obb obd obn obo obs oda odb odd odn odo ods on- ona onb ond onn ono ons oo- ooa oob ood oon ooo oos os- osa osb osd osn oso oss saa sab sad san sao sas sba sbb sbd sbn sbo sbs sda sdb sdd sdn sdo sds sna snb snd snn sno sns soa sob sod son soo sos ss- ssa ssb ssd ssn sso sss