A potato is dropped into a cylindrical glass with a bottom radius of 2 cm and a water level of 3 cm. The water level rises by 1 cm. What is the volume of the potato in cubic centimeters?
将一个土豆投入一个底面半径为2厘米，水位高为3厘米的圆柱形玻璃杯中，水面上升了1厘米，这块土豆的体积是多少立方厘米．
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4 * 1</gadget>
<output>12.56</output>

<result>12.56</result>