a-a a-b aaa aab aad aaf aao aas aay ab- aba abb abd abf abo abs aby ad- ada adb add adf ado ads ady af- afa afb afd aff afo afs afy aoa aob aod aof aoo aos as- asa asb asd asf aso ass asy ay- aya ayd ayf ayo ays baa bab bad baf bao bas bay bba bbb bbd bbf bbo bbs bby bda bdb bdd bdf bdo bds bdy bfa bfb bfd bff bfo bfs bfy boa bob bod bof boo bos boy bsa bsb bsd bsf bso bss bsy by- bya byd byf byo bys daa dab dad daf dao das day dba dbb dbd dbf dbo dbs dby dda ddb ddd ddf ddo dds ddy dfa dfb dfd dff dfo dfs doa dob dod dof doo dos doy dsa dsb dsd dsf dso dss dsy dy- dya dyb dyd dyo dys dyy faa fab fad faf fao fas fay fba fbb fbd fbf fbo fbs fda fdb fdd fdf fdo fds ffa ffd fff ffo ffs ffy foa fob fof foo fos foy fsa fsb fsd fsf fso fss fy- fya fyb fyo oaa oab oad oaf oao oas ob- oba obb obd obf obo obs oby oda odb odd odf odo ods of- ofa ofb ofd off ofo ofs oo- ooa oob ood oof ooo oos os- osa osb osd osf oso oss oya oyd oyo oys saa sab sad saf sao sas say sba sbb sbd sbf sbo sbs sby sda sdb sdd sdf sdo sds sdy sfa sfb sfd sff sfo sfs soa sob sod sof soo sos soy ss- ssa ssb ssd ssf sso sss sy- sya syb syd sys yaa yab yad yaf yao yas yay ybf ybs yby yda ydo yds ydy yfa yfd yff yfs yob yod yof yoo yos yoy ysa ysb yso yss ysy yyb yyf yys yyy