Your task is to write a program, which, given two circles,
calculates the area of their intersection with the accuracy of two
digits after decimal point.

Input file format

In the single line of input file there are space-separated real numbers
x_{1}y_{1}r_{1}x_{2}y_{2}r_{2}.
They represent center coordinates and radii of two circles.

Output file format

The output file must contain single real number — the area.