description: You are given n integers a_1, a_2, …, a_n. Find the maximum value of max(a_l, a_{l + 1}, …, a_r) ⋅ min(a_l, a_{l + 1}, …, a_r) over all pairs (l, r) of integers for which 1 ≤ l < r ≤ n.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 10 000) — the number of test cases.
  
  The first line of each test case contains a single integer n (2 ≤ n ≤ 10^5).
  
  The second line of each test case contains n integers a_1, a_2, …, a_n (1 ≤ a_i ≤ 10^6).
  
  It is guaranteed that the sum of n over all test cases doesn't exceed 3 ⋅ 10^5.
  
  Output
  
  For each test case, print a single integer — the maximum possible value of the product from the statement.
  
  Example
  
  Input
  
  
  4
  3
  2 4 3
  4
  3 2 3 1
  2
  69 69
  6
  719313 273225 402638 473783 804745 323328
  
  
  Output
  
  
  12
  6
  4761
  381274500335
  
  Note
  
  Let f(l, r) = max(a_l, a_{l + 1}, …, a_r) ⋅ min(a_l, a_{l + 1}, …, a_r).
  
  In the first test case, 
  
    * f(1, 2) = max(a_1, a_2) ⋅ min(a_1, a_2) = max(2, 4) ⋅ min(2, 4) = 4 ⋅ 2 = 8. 
    * f(1, 3) = max(a_1, a_2, a_3) ⋅ min(a_1, a_2, a_3) = max(2, 4, 3) ⋅ min(2, 4, 3) = 4 ⋅ 2 = 8. 
    * f(2, 3) = max(a_2, a_3) ⋅ min(a_2, a_3) = max(4, 3) ⋅ min(4, 3) = 4 ⋅ 3 = 12. 
  
  
  
  So the maximum is f(2, 3) = 12.
  
  In the second test case, the maximum is f(1, 2) = f(1, 3) = f(2, 3) = 6.
solution: import collections
  import random
  import math
  from collections import defaultdict
  import itertools
  from sys import stdin, stdout
  import sys
  import operator
  from decimal import Decimal
  
  # sys.setrecursionlimit(10**6)
  
  p2D = lambda x: print(*x, sep="\n")
  def II(): return int(sys.stdin.buffer.readline())
  def MI(): return map(int, sys.stdin.buffer.readline().split())
  def LI(): return list(map(int, sys.stdin.buffer.readline().split()))
  def LLI(rows_number): return [LI() for _ in range(rows_number)]
  def BI(): return sys.stdin.buffer.readline().rstrip()
  def SI(): return sys.stdin.buffer.readline().rstrip().decode()
  def li(): return [int(i) for i in input().split()]
  def lli(rows): return [li() for _ in range(rows)]
  def si(): return input()
  def ii(): return int(input())
  def ins(): return input().split()
  
  
  def main():
      # z = ''
      # p = lambda *a: print(*a, flush = True)
      # mod = 10 ** 9 + 7
      for _ in range(ii()):
          n = ii()
          a = li()
          m = 0
          for i in range(1,n):
              if a[i-1]*a[i]>m:
                  m = a[i-1]*a[i]
          print(m)
  
      #     z += str(ans) + '\n'
      # print(len(ans), ' '.join(map(str, ans)), sep='\n')
      # stdout.write(z)
  
  
  # for interactive problems
  # print("? {} {}".format(l,m), flush=True)
  # or print this after each print statement
  # sys.stdout.flush()
  
  
  if __name__ == "__main__":
      main()