If the radius of a circle is 1 decimeter, what is the circumference of its semicircle?
一个圆的半径是1分米，它的半圆周长是多少分米．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

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

<gadget id="calculator">1 * 2</gadget>
<output>2</output>

<gadget id="calculator">3.14 + 2</gadget>
<output>5.14</output>

<result>5.14</result>