To make a cylindrical iron bucket without a cover, the height is 30 cm, and the radius of the bottom is 10 cm. How many square centimeters of iron sheet are needed to make this bucket?
做一个无盖的圆柱形铁皮水桶，高30厘米，底面半径是10厘米，做这个水桶至少需要多少平方厘米的铁皮？
<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<gadget id="calculator">2 * 3.14 * 10 * 30</gadget>
<output>1_884</output>

<gadget id="calculator">314 + 1_884</gadget>
<output>2_198</output>

<result>2_198</result>