B'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 <= q T <= q 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 <= q n <= q 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 <= q a_i <= q 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. '...