Problem U. Circular Area

Author:Far-Eastern Subregional   Time limit:3 sec
Input file:input.txt   Memory limit:8 Mb
Output file:output.txt  


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 x1 y1 r1 x2 y2 r2. They represent center coordinates and radii of two circles.

Output file format

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

Sample tests

No. Input file (input.txt) Output file (output.txt)
20.0 30.0 15.0 40.0 30.0 30.0

0.205s 0.118s 13