A cylindrical wooden barrel with a bottom radius of 5 decimeters and a depth of 8 decimeters, if two iron hoops are added outside it, and the joints overlap by 0.3 decimeters, how many decimeters are needed to make such two iron hoops Tin bars?
一个底面半径为5分米，深为8分米的圆柱形木桶，如果在他的外面加两条铁箍，接头处重叠0.3分米，做这样的两条铁箍需要多少分米长的铁皮条？
<gadget id="calculator">2 * 3.14 * 5</gadget>
<output>31.4</output>

<gadget id="calculator">31.4 + 0.3</gadget>
<output>31.7</output>

<gadget id="calculator">31.7 * 2</gadget>
<output>63.4</output>

<result>63.4</result>