Fence
In the city of N-sk, plans have been made to construct a new skyscraper. To secure the construction site, rectangular concrete blocks have been delivered. While all blocks share the same width, their lengths may differ. The construction manager aims to enclose the maximum possible area using all the available blocks, regardless of the cost.
Input
The input begins with a line indicating the number of test cases. For each test case, the first line specifies an integer N (3 ≤ N ≤ 100), which represents the number of blocks. The second line lists N integers, separated by spaces, denoting the lengths L_i of the blocks (natural numbers, 1 ≤ L_i ≤ 100). It is assured that the polygon formed by these blocks can be circumscribed by a circle.
Output
For each test case, output the largest area that can be enclosed using the given set of blocks, with the result formatted to two decimal places. The width of the blocks is negligible, treating them as line segments.