There is a pile of logs of uniform thickness in a trapezoidal shape. There are 3 logs on the top layer, and one is added to the next layer. There are 22 logs on the bottom layer. There are 20 layers in total. How many logs are there in total?
有一堆粗细均匀的圆木，堆成梯形，最上面的一层有3根圆木，每向下一层增加一根，最下面的一层有22根圆木，一共堆了20层，这堆圆木一共有多少根？
<gadget id="calculator">3 + 22</gadget>
<output>25</output>

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

<gadget id="calculator">25 * 10</gadget>
<output>250</output>

<result>250</result>