A circular fountain with a circumference of 12.56 meters needs to build a gravel road with a width of 1m around it. How many square meters does the gravel road occupy?
一个周长是12.56米的圆形喷水池，要在它周围修一条1m宽的石子路，石子路的占地面积是多少平方米？
<gadget id="calculator">2 * 3.14</gadget>
<output>6.28</output>

<gadget id="calculator">12.56 / 6.28</gadget>
<output>2</output>

<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<gadget id="calculator">28.26 - 12.56</gadget>
<output>15.7</output>

<result>15.7</result>