# Circular Area

Time Limit: 1 Second Memory Limit: 32768 KB

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.

## Input

In the single line of input file there are space-separated real numbers x1 y1 r1 x2 y2 r2. They represent center coordinates and radii of two circles.

Process to the end of input.

## Output

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

## Sample Input

20.0 30.0 15.0 40.0 30.0 30.0

## Sample Output

608.366Submit

Source: Northeastern Europe 2000, Far-Eastern Subregion