Problem A. Circular Area ≡

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

Statement

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)
1	20.0 30.0 15.0 40.0 30.0 30.0 copy	608.37 copy

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