a-a a-b a-c aaa aab aac aan aas aay ab- aba abb abc abn abs aby ac- aca acb acc acn acs acy an- ana anb anc ann ans any as- asa asb asc asn ass asy ay- aya ayc ayn ays baa bab bac ban bas bay bba bbb bbc bbn bbs bby bca bcb bcc bcn bcs bcy bna bnb bnc bnn bns bsa bsb bsc bsn bss bsy by- bya byc byn bys c-- caa cab cac can cas cay cba cbb cbc cbn cbs cby cca ccb ccc ccn ccs cn- cna cnb cnc cnn cns cny csa csb csc csn css csy cya cyb cyc cyn cys naa nab nac nan nas nay nba nbb nbc nbn nbs nca ncb ncc ncn ncs nna nnb nnc nnn nns nsa nsb nsc nsn nss nsy nya nyc nyn nys nyy saa sab sac san sas say sba sbb sbc sbn sbs sby sca scb scc scn scs sna snb snc snn sns sny ss- ssa ssb ssc ssn sss sy- sya syb syc syn sys yaa yab yac yan yas yay ybc ybs yby yca ycc ycs ycy yna ynn yns yny ysa ysb ysc yss ysy yyb yyc yys yyy