Cut out 4 largest and equal circles from a square cardboard with a side length of 4 decimeters, what is the area of the remaining part?
在一个边长是4分米的正方形纸板上，剪下4个最大而且相等的圆，剩余部分的面积是多少．
<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">4 / 2 / 2</gadget>
<output>1</output>

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

<gadget id="calculator">3.14 * 1 * 4</gadget>
<output>12.56</output>

<gadget id="calculator">16 - 12.56</gadget>
<output>3.44</output>

<result>3.44</result>