CIRU  The area of the union of circles
You are given N circles and expected to calculate the area of the union of the circles !
Input
The first line is one integer n indicates the number of the circles. (1 <= n <= 1000)
Then follows n lines every line has three integers
Xi Yi Ri
indicates the coordinate of the center of the circle, and the radius. (Xi. Yi <= 1000, Ri <= 1000)
Note that in this problem Ri may be 0 and it just means one point !
Output
The total area that these N circles with 3 digits after decimal point
Example
Input:
3
0 0 1
0 0 1
100 100 1
Output:
6.283
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mike_nzk:
20110418 16:18:31
oh, no!!! Simpson's method is too slow and eps must be carefully selected, although I got AC at the first time.

Added by:  aekdycoin 
Date:  20101215 
Time limit:  0.100s2.235s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ASM64 
Resource:  https://www.spoj.pl/problems/VCIRCLES/ 