A semicircular piece of paper has a radius of 1 decimeter. To cut such a semicircle, at least one rectangular piece of paper with an area of how many square decimeters is required.
一张半圆形纸片半径是1分米，要剪成这样的一个半圆形，至少要一张面积是多少平方分米的长方形纸片．
<gadget id="calculator">1 * 2 * 1</gadget>
<output>2</output>

<result>2</result>