A pile of logs is neatly stacked on the ground, with 25 logs on the bottom layer and 6 logs on the top layer, and each lower layer has one more than the upper layer. How many logs are there in this pile?
一堆木头整齐地叠放在地上，最下面一层有25根，最上面一层有6根，每下面一层都要比它上面一层多一根．这堆木头一共有几根？
<gadget id="calculator">25 + 6</gadget>
<output>31</output>

<gadget id="calculator">25 - 6</gadget>
<output>19</output>

<gadget id="calculator">19 + 1</gadget>
<output>20</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">31 * 10</gadget>
<output>310</output>

<result>310</result>