bbb bbi bbk bbs bby bi- bib bii bik bis biy bkb bkk bks bsb bsi bsk bss bsy by- byi byk bys ibb ibi ibk ibs iby iib iii iis ikb iki ikk iks is- isb isi isk iss isy iys iyy kbb kbi kbk kbs kib kii kik kis kkb kki kkk kks kky ksb ksi ksk kss kys sbb sbi sbk sbs sby sib sii sik sis sk- skb ski skk sks sky ss- ssb ssi ssk sss sy- syb syi syk sys ybi ybs yby yii yis yki ykk ysb ysi ysk yss ysy yyb yys yyy