It's Chinese New Year, and Xiaogang wants to organize his CDs. If there are 5 pieces in each box, one plate is missing 1 piece; if there are 6 pieces in each box, exactly one box is used less. How many pieces of Xiaogang's CDs are there?
过年了，小刚想把自己的光盘整理一下．若每盒5片，则有一盘少了1片；若每盒6片，则恰好少用一个盒子．小刚的光盘一共有多少片．
<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">6 - 5</gadget>
<output>1</output>

<gadget id="calculator">5 / 1</gadget>
<output>5</output>

<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<gadget id="calculator">25 - 1</gadget>
<output>24</output>

<result>24</result>