A straight cylinder with a height of 1 meter, if its height is shortened by 2 decimeters, its surface area will be reduced by 12.56 square decimeters. What is the volume of the original right cylinder in cubic decimeters?
一根高1米的直圆柱木料，如果把它的高缩短2分米后，它的表面积就减少12.56平方分米．原来直圆柱体积是多少立方分米．
<gadget id="calculator">12.56 / 2 / 3.14 / 2</gadget>
<output>1</output>

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

<gadget id="calculator">3.14 * 1 * 1 * 10</gadget>
<output>31.4</output>

<result>31.4</result>