The length of a rectangle is 9cm, the width is 6cm, and a circle with a radius of 1 rolls arbitrarily within the rectangle. What is the area of the part that the circle cannot move within the rectangle?
一个长方形的长为9cm，宽为6cm，一个半径为1的圆在这个长方形内任意滚动，在长方形内这个圆无法运动到的部分的面积是多少？
<gadget id="calculator">1 * 2 * 2</gadget>
<output>4</output>

<gadget id="calculator">9 - 4</gadget>
<output>5</output>

<gadget id="calculator">6 - 4</gadget>
<output>2</output>

<gadget id="calculator">5 * 2</gadget>
<output>10</output>

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

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

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

<gadget id="calculator">4 - 3.14</gadget>
<output>0.86</output>

<gadget id="calculator">10 + 0.86</gadget>
<output>10.86</output>

<result>10.86</result>