a-a a-b aaa aab aas aau aay ab- aba abb abs abu aby as- asa asb ass asu asy au- aua aub aus ay- aya ays ayu b-u baa bab bas bau bay bba bbb bbs bbu bby bsa bsb bss bsu bsy bua bub bus buu buy by- bya bys byu saa sab sas sau say sba sbb sbs sbu sby ss- ssa ssb sss ssu sua sub sus suu suy sy- sya syb sys syu ua- uaa uab uas uau uay uba ubb ubs ubu uby usa usb uss usu uua uus uuu uys uyu yaa yab yas yau yay ybs yby ysa ysb yss ysu ysy yua yus yuu yuy yyb yys yyu yyy