a-a a-b aaa aab aar aas aay ab- aba abb abr abs aby ar- ara arb arr ars ary as- asa asb asr ass asy ay- aya ayr ays baa bab bar bas bay bba bbb bbr bbs bby bra brb brr brs bry bsa bsb bsr bss bsy by- bya byr bys ra- raa rab rar ras ray rba rbb rbr rbs rra rrb rrr rrs rsa rsb rsr rss ry- rya ryr rys ryy saa sab sar sas say sba sbb sbr sbs sby sr- sra srb srr srs sry ss- ssa ssb ssr sss sy- sya syb syr sys yaa yab yar yas yay ybr ybs yby yra yrs ysa ysb ysr yss ysy yyb yys yyy