a-a a-b a-t aaa aab aad aao aas aat aay ab- aba abb abd abo abs abt aby ad- ada adb add ado ads adt ady aoa aob aod aoo aos aot as- asa asb asd aso ass ast asy at- ata atb atd ato ats att ay- aya ayd ayo ays ayt baa bab bad bao bas bat bay bba bbb bbd bbo bbs bbt bby bda bdb bdd bdo bds bdt bdy boa bob bod boo bos bot boy bsa bsb bsd bso bss bst bsy bta btb btd bto bts btt bty by- bya byd byo bys byt daa dab dad dao das dat day dba dbb dbd dbo dbs dbt dby dda ddb ddd ddo dds ddt ddy doa dob dod doo dos dot doy dsa dsb dsd dso dss dst dsy dta dtb dtd dto dts dtt dty dy- dya dyb dyd dyo dys dyy oaa oab oad oao oas oat ob- oba obb obd obo obs obt oby oda odb odd odo ods odt oo- ooa oob ood ooo oos oot os- osa osb osd oso oss ost ot- ota otb otd oto ots ott oya oyd oyo oys saa sab sad sao sas sat say sba sbb sbd sbo sbs sbt sby sda sdb sdd sdo sds sdt sdy soa sob sod soo sos sot soy ss- ssa ssb ssd sso sss sst sta stb std sto sts stt sty sy- sya syb syd sys syt taa tab tad tao tas tat tay tba tbb tbd tbo tbs tbt tda tdb tdd tdo tds tdt tdy to- toa tob tod too tos tot toy tsa tsb tsd tso tss tst tsy tta ttb ttd tto tts ttt tty tya tyd tyo tys tyt yaa yab yad yao yas yat yay ybs yby yda ydo yds ydt ydy yob yod yoo yos yot yoy ysa ysb yso yss yst ysy yta ytd yto yts ytt yyb yys yyt yyy