a-a a-b a-c aaa aab aac aad aan aas ab- aba abb abc abd abn abs ac- aca acb acc acd acn acs ad- ada adb adc add adn ads an- ana anb anc and ann ans as- asa asb asc asd asn ass baa bab bac bad ban bas bba bbb bbc bbd bbn bbs bca bcb bcc bcd bcn bcs bda bdb bdc bdd bds bna bnb bnc bnd bnn bns bsa bsb bsc bsd bsn bss c-- caa cab cac cad can cas cba cbb cbc cbd cbn cbs cca ccb ccc ccd ccn ccs cda cdb cdc cdd cdn cds cn- cna cnb cnc cnd cnn cns csa csb csc csd csn css daa dab dac dad dan das dba dbb dbc dbd dbn dbs dca dcb dcc dcd dcn dcs dda ddb ddc ddd ddn dds dna dnb dnc dnd dnn dns dsa dsb dsc dsd dsn dss naa nab nac nad nan nas nba nbb nbc nbd nbn nbs nca ncb ncc ncd ncn ncs nda ndb ndc ndd ndn nds nna nnb nnc nnn nns nsa nsb nsc nsd nsn nss saa sab sac sad san sas sba sbb sbc sbd sbn sbs sca scb scc scd scn scs sda sdb sdc sdd sdn sds sna snb snc snd snn sns ss- ssa ssb ssc ssd ssn sss