bbbb bbbs bbin bibb bibi bibs biin biis bin- bini binn bins binu bis- biss bisu bnib bnin bnss bsin bsns bubb bubi bubs bubu buin buis buiu bunb buni bunn buns bunu busi buss busu buus ibis ibns ibsn ibss ibus iiii iiis iisi iisu inis inni inns innu inss insu inui inun inus isbn isin isis issi isss issu isus iuiu iuss n-ii nibi nibs niiu nini nins nisi niss nisu nnnn nnss nsin nsis nssb nsss nsub nubi nubs nuin nunn nuns nusi nuss nusu s-ib s-ii sbbs sbsi sbus sibi sibs sibu sini sinn sins sinu sisi siss sisu siui sius snib snns snub snus ssbn ssin ssis ssns sssb sssi ssss sub- subb subi subs suin suis sun- sunb suni sunn suns sunu sus- susi suss susu suus ubbi ubii ubis uni- unii unin unis unni unns uns- unus usbs usin usis usnu ussb usss ussu usui usun usus uuni uusi uuuu