There are 17 logs in the top layer, 40 logs in the bottom layer, and one more log in the lower layer than the upper layer. How many logs are there in this pile?
有一堆圆木，最上面那层有17根，最下面那层有40根，下一层比上一层多一根，请问这堆圆木共有多少根？
<gadget id="calculator">17 + 40</gadget>
<output>57</output>

<gadget id="calculator">40 - 17</gadget>
<output>23</output>

<gadget id="calculator">23 + 1</gadget>
<output>24</output>

<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<gadget id="calculator">57 * 12</gadget>
<output>684</output>

<result>684</result>