A cylindrical iron can containing milk powder has a bottom circumference of 31.4cm and a height of 1.5dm. How many square centimeters of iron sheet is needed to make such an iron can?
一个盛奶粉的圆柱形铁罐，底面周长是31.4cm，高是1.5dm，做一个这样的铁罐至少需用多少平方厘米铁皮？
<gadget id="calculator">1.5 * 10</gadget>
<output>15</output>

<gadget id="calculator">31.4 * 15</gadget>
<output>471</output>

<gadget id="calculator">31.4 / 3.14 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25 * 2</gadget>
<output>157</output>

<gadget id="calculator">471 + 157</gadget>
<output>628</output>

<result>628</result>