A certain school has a number of balls, if they are distributed to 9 classes on average, there will be 8 balls left, if they are distributed to 10 classes on average, there will be 9 balls left, if they are distributed to 15 classes on average, there will be 14 balls left, what is the minimum number of balls in the school?
某校有皮球若干个，如平均分给9个班则余下8个，如平均分给10个班则余下9个，如平均分给15个班则余下14个，学校至少有多少个皮球．
<gadget id="calculator">2 * 3 * 3 * 5</gadget>
<output>90</output>

<gadget id="calculator">90 - 1</gadget>
<output>89</output>

<result>89</result>