a-a a-b a-t aaa aab aad aao aat aay ab- aba abb abd abo abt aby ad- ada adb add ado adt ady aoa aob aod aoo aot at- ata atb atd ato att ay- aya ayd ayo ayt baa bab bad bao bat bay bba bbb bbd bbo bbt bby bda bdb bdd bdo bdt bdy boa bob bod boo bot boy bta btb btd bto btt bty by- bya byd byo byt daa dab dad dao dat day dba dbb dbd dbo dbt dby dda ddb ddd ddo ddt ddy doa dob dod doo dot doy dta dtb dtd dto dtt dty dy- dya dyb dyd dyo dyy oaa oab oad oao oat ob- oba obb obd obo obt oby oda odb odd odo odt oo- ooa oob ood ooo oot ot- ota otb otd oto ott oya oyd oyo taa tab tad tao tat tay tba tbb tbd tbo tbt tda tdb tdd tdo tdt tdy to- toa tob tod too tot toy tta ttb ttd tto ttt tty tya tyd tyo tyt yaa yab yad yao yat yay yby yda ydo ydt ydy yob yod yoo yot yoy yta ytd yto ytt yyb yyt yyy