You are given $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$. For any real number $$$t$$$, consider the complete weighted graph on $$$n$$$ vertices $$$K_n(t)$$$ with weight of the edge between vertices $$$i$$$ and $$$j$$$ equal to $$$w_{ij}(t) = a_i \cdot a_j + t \cdot (a_i + a_j)$$$.
Let $$$f(t)$$$ be the cost of the minimum spanning tree of $$$K_n(t)$$$. Determine whether $$$f(t)$$$ is bounded above and, if so, output the maximum value it attains.
The input consists of multiple test cases. The first line contains a single integer $$$T$$$ ($$$1 \leq T \leq 10^4$$$) — the number of test cases. Description of the test cases follows.
The first line of each test case contains an integer $$$n$$$ ($$$2 \leq n \leq 2 \cdot 10^5$$$) — the number of vertices of the graph.
The second line of each test case contains $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$ ($$$-10^6 \leq a_i \leq 10^6$$$).
The sum of $$$n$$$ for all test cases is at most $$$2 \cdot 10^5$$$.
For each test case, print a single line with the maximum value of $$$f(t)$$$ (it can be shown that it is an integer), or INF if $$$f(t)$$$ is not bounded above.
521 02-1 131 -1 -233 -1 -241 2 3 -4
INF -1 INF -6 -18
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