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: #    ____                       _   _                _     _ _   
  #   / ___| __ _ _ __ __ _      | | | | __ _ _ __ ___| |__ (_) |_ 
  #  | |  _ / _` | '__/ _` |_____| |_| |/ _` | '__/ __| '_ \| | __|
  #  | |_| | (_| | | | (_| |_____|  _  | (_| | |  \__ \ | | | | |_ 
  #   \____|\__,_|_|  \__, |     |_| |_|\__,_|_|  |___/_| |_|_|\__|
  #                   |___/                                        
  
  from typing import Counter
  import sys
  from collections import defaultdict as dd
  from math import *
  
  def vinp():
      return map(int,input().split())
  def linp():
      return list(map(int,input().split()))
  def sinp():
      return input()
  def inp():
      return int(input())
  def mod(f):
      return f % 1000000007
  def pr(*x):
      print(*x)
  def finp():
      f=open("input.txt","r")
      f=f.read().split("\n")
      return f
  def finp():
      f=open("input.txt","r")
      f=f.read().split("\n")
      return f
  def fout():
      return open("output.txt","w")
  def fpr(f,x):
      f.write(x+"\n")
  def csort(c):
      sorted(c.items(), key=lambda pair: pair[1], reverse=True)
  def indc(l,n):
      c={}
      for i in range(n):
          c[l[i]]=c.get(l[i],[])+[i+1]
      return c
  
  if __name__ =="__main__":
      cou=inp()
      for i in range(cou):
          n=inp()
          l=linp()
          ans=0
          for i in range(n-1):
              a=min(l[i],l[i + 1])
              b=max(l[i],l[i + 1])
              ans = max(ans,a*b)
          pr(ans)