Given $$$n$$$ triangles on the same grid ( more than $$$1$$$ ). Calculate the total area these triangle cover (they may be overlap or not).

Can you help me to approach this problem? Thanks a lot.

Input:

• The first line represents number $$$n$$$ .

• $$$n$$$ lines follow, each line represent 6 integers — the vertices of the triangle $$$i$$$ ($$$-10^{6}$$$ ≤ $$$x$$$, $$$y$$$ ≤ $$$10^{6}$$$ ).

Output: The area which $$$n$$$ triangles cover on. The difference between your output and the answer must be smaller than $$$10^{-6}$$$ .

Sample input:

3

1 1 5 1 3 3

1 2 5 2 5 6

1 6 5 2 1 2

Sample Output:

15.000000