You are given (n) sticks, where the (i)-th stick has a length of (a_i). You want to choose a non-empty subset of these sticks and use them as the sides of a polygon. Each selected stick must be used entirely as a single side of the polygon. It is not allowed for two or more sticks to be joined end-to-end in parallel to form a longer side. Your goal is to form a polygon that is symmetrical, strictly convex, and non-degenerate: Symmetrical : there exists a line of symmetry such that when the polygon is folded along this line, the two halves coincide exactly. Strictly convex : all its internal angles are strictly less than (180^\circ). Non-degenerate : no two consecutive sides coincide at least partially, no side has zero length, and no angle equals (180^\circ). Among all such polygons that you can form with the sticks, find the maximum possible perimeter(^{\text{∗}}). If no valid polygon exists, output (0). (^{\text{∗}})The perimeter of a polygon is equal to the sum of the lengths of its sides. Each test contains multiple test cases. The first line contains the number of test cases (t) ((1 \le t \le 10^4)). The description of the test cases follows. The first line of each test case contains a single integer (n) ((3\le n\le 2\cdot 10^5)) — the number of sticks. The second line of each test case contains (n) integers (a_1, a_2, \ldots, a_n) ((1\le a_i\le 10^9)) — the lengths of the sticks. It is guaranteed that the sum of (n) over all test cases does not exceed (2\cdot 10^5). For each test case, output a single integer representing the maximum possible perimeter of a non-degenerate, symmetrical and strictly convex polygon that you can form from a non-empty subset of the sticks. If it is not possible, output (0). In the first test case, you can form an isosceles triangle using all three sticks. It is symmetrical along the vertical dotted line (see left diagram). The perimeter is equal to th