bbb bbi bbr bbs bby bi- bib bii bir bis biy brb bri brr brs bry bsb bsi bsr bss bsy by- byi byr bys ibb ibi ibr ibs iby iib iii iir iis ir- irb iri irr irs iry is- isb isi isr iss isy iyr iys iyy rbb rbi rbr rbs rib rii rir ris riy rrb rri rrr rrs rsb rsi rsr rss ry- ryr rys ryy sbb sbi sbr sbs sby sib sii sir sis sr- srb sri srr srs sry ss- ssb ssi ssr sss sy- syb syi syr sys ybi ybr ybs yby yii yir yis yrs ysb ysi ysr yss ysy yyb yys yyy