Two circles have areas of 24 square centimeters and 31 square centimeters respectively, and the area of the overlapped part of the two circles is 43 square centimeters. Find the area of the overlapping part.
两个圆，面积分别是24平方厘米和31平方厘米，两圆部分重叠后的面积是43平方厘米，求重叠部分的面积．
<gadget id="calculator">31 - 43</gadget>
<output>-12</output>

<gadget id="calculator">24 + (-12)</gadget>
<output>12</output>

<result>12</result>