a-a a-b a-t aaa aab aad aaf aao aat aau ab- aba abb abd abf abo abt abu ad- ada adb add adf ado adt adu af- afa afb afd aff afo aft afu aoa aob aod aof aoo aot aou at- ata atb atd atf ato att atu au- aua aub aud auf auo aut b-u baa bab bad baf bao bat bau bba bbb bbd bbf bbo bbt bbu bda bdb bdd bdf bdo bdt bdu bfa bfb bfd bff bfo bft bfu boa bob bod bof boo bot bou bta btb btd btf bto btt btu bua bub bud buf buo but buu daa dab dad daf dao dat dau dba dbb dbd dbf dbo dbt dbu dda ddb ddd ddf ddo ddt ddu dfa dfb dfd dff dfo dft dfu doa dob dod dof doo dot dou dta dtb dtd dtf dto dtt dtu dua dub dud duf duo dut faa fab fad faf fao fat fau fba fbb fbd fbf fbo fbt fbu fda fdb fdd fdf fdo fdt fdu ffa ffd fff ffo fft ffu foa fob fof foo fot fou fta ftb ftd ftf fto ftt ftu fua fub fud fuf fuo fut fuu oaa oab oad oaf oao oat oau ob- oba obb obd obf obo obt obu oda odb odd odf odo odt odu of- ofa ofb ofd off ofo oft ofu oo- ooa oob ood oof ooo oot ot- ota otb otd otf oto ott otu ou- oua oud ouf ouo out taa tab tad taf tao tat tau tba tbb tbd tbf tbo tbt tbu tda tdb tdd tdf tdo tdt tdu tfa tfb tfd tff tfo tft tfu to- toa tob tod tof too tot tou tta ttb ttd ttf tto ttt ttu tua tub tud tuf tuo tut tuu ua- uaa uab uad uaf uao uat uau uba ubb ubf ubo ubt ubu uda udb udd udf udo udt udu ufa ufd uff ufo uft ufu uoa uob uod uoo uot uta utb utd utf uto utt utu uua uut uuu