a-a a-t aaa aad aaf aao aat ad- ada add adf ado adt af- afa afd aff afo aft aoa aod aof aoo aot at- ata atd atf ato att daa dad daf dao dat dda ddd ddf ddo ddt dfa dfd dff dfo dft doa dod dof doo dot dta dtd dtf dto dtt faa fad faf fao fat fda fdd fdf fdo fdt ffa ffd fff ffo fft foa fof foo fot fta ftd ftf fto ftt oaa oad oaf oao oat oda odd odf odo odt of- ofa ofd off ofo oft oo- ooa ood oof ooo oot ot- ota otd otf oto ott taa tad taf tao tat tda tdd tdf tdo tdt tfa tfd tff tfo tft to- toa tod tof too tot tta ttd ttf tto ttt