To make a cylindrical iron sheet bucket without a cover, the height is 4 decimeters, and the radius of the bottom surface is 2 decimeters. How many square decimeters of iron sheet should be used to make this bucket?
做一个不带盖的圆柱形铁皮水桶，高是4分米，底面半径是2分米，做这个水桶至少要用多少平方分米铁皮？
<gadget id="calculator">3.14 * 2 * 2 * 4</gadget>
<output>50.24</output>

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

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

<gadget id="calculator">50.24 + 12.56</gadget>
<output>62.8</output>

<result>62.8</result>