a-a a-b a-t aaa aab aad aao aat aau ab- aba abb abd abo abt abu ad- ada adb add ado adt adu aoa aob aod aoo aot aou at- ata atb atd ato att atu au- aua aub aud auo aut b-u baa bab bad bao bat bau bba bbb bbd bbo bbt bbu bda bdb bdd bdo bdt bdu boa bob bod boo bot bou bta btb btd bto btt btu bua bub bud buo but buu daa dab dad dao dat dau dba dbb dbd dbo dbt dbu dda ddb ddd ddo ddt ddu doa dob dod doo dot dou dta dtb dtd dto dtt dtu dua dub dud duo dut oaa oab oad oao oat oau ob- oba obb obd obo obt obu oda odb odd odo odt odu oo- ooa oob ood ooo oot ot- ota otb otd oto ott otu ou- oua oud ouo out taa tab tad tao tat tau tba tbb tbd tbo tbt tbu tda tdb tdd tdo tdt tdu to- toa tob tod too tot tou tta ttb ttd tto ttt ttu tua tub tud tuo tut tuu ua- uaa uab uad uao uat uau uba ubb ubo ubt ubu uda udb udd udo udt udu uoa uob uod uoo uot uta utb utd uto utt utu uua uut uuu