a-a a-b aaa aab aad aas aay ab- aba abb abd abs aby ad- ada adb add ads ady as- asa asb asd ass asy ay- aya ayd ays baa bab bad bas bay bba bbb bbd bbs bby bda bdb bdd bds bdy bsa bsb bsd bss bsy by- bya byd bys daa dab dad das day dba dbb dbd dbs dby dda ddb ddd dds ddy dsa dsb dsd dss dsy dy- dya dyb dyd dys dyy saa sab sad sas say sba sbb sbd sbs sby sda sdb sdd sds sdy ss- ssa ssb ssd sss sy- sya syb syd sys yaa yab yad yas yay ybs yby yda yds ydy ysa ysb yss ysy yyb yys yyy