
ZOJ Problem Set  1597
Your task is to write a program, which, given two circles, calculates the area of their intersection with the accuracy of three digits after decimal point.
In the single line of input file there are spaceseparated real numbers x1 y1 r1 x2 y2 r2. They represent center coordinates and radii of two circles. Process to the end of input.
20.0 30.0 15.0 40.0 30.0 30.0
608.366 Source: Northeastern Europe 2000, FarEastern Subregion 