Tell me the area

    There are two circles in the plane (shown in the below picture), there is a common area between the two circles. The problem is easy that you just tell me the common area.

There are many cases. In each case, there are two lines. Each line has three numbers: the coordinates (X and Y) of the centre of a circle, and the radius of the circle.

For each case, you just print the common area which is rounded to three digits after the decimal point. For more details, just look at the sample.

0 0 2
2 2 1

0.108

wangye

2008 “Insigma International Cup” Zhejiang Collegiate Programming Contest - Warm Up（4）