a-a a-b a-t aaa aab aas aat aau aay ab- aba abb abs abt abu aby as- asa asb ass ast asu asy at- ata atb ats att atu au- aua aub aus aut ay- aya ays ayt ayu b-u baa bab bas bat bau bay bba bbb bbs bbt bbu bby bsa bsb bss bst bsu bsy bta btb bts btt btu bty bua bub bus but buu buy by- bya bys byt byu saa sab sas sat sau say sba sbb sbs sbt sbu sby ss- ssa ssb sss sst ssu sta stb sts stt stu sty sua sub sus sut suu suy sy- sya syb sys syt syu taa tab tas tat tau tay tba tbb tbs tbt tbu tsa tsb tss tst tsu tsy tta ttb tts ttt ttu tty tua tub tus tut tuu tuy tya tys tyt ua- uaa uab uas uat uau uay uba ubb ubs ubt ubu uby usa usb uss ust usu uta utb uts utt utu uty uua uus uut uuu uys uyu yaa yab yas yat yau yay ybs yby ysa ysb yss yst ysu ysy yta yts ytt ytu yua yus yut yuu yuy yyb yys yyt yyu yyy