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: # python
  import os
  import sys; import math
  from io import BytesIO, IOBase
  from operator import itemgetter
  
  def solve():
      n = int(input()); a = [int(x) for x in input().split()]
      Max = -99999999999999999999999
      for i in range(n-1):
          Max = max(Max,a[i]*a[i+1])
      print(Max)
  
  
  
  
  def upperbound(arr,val):
      start = 0; end = len(arr) - 1; ans = -1
      while (start <= end):
          mid = (start + end) // 2
          if (arr[mid] <= val):
              start = mid + 1
          else:
              ans = mid
              end = mid - 1
      return ans
  def lowerbound(arr,val):
      length = len(arr); answer = -1; start = 0; end = length - 1    
      while start <= end:
          middle = (start + end)//2    
          if arr[middle] == val:
              answer = middle
              end = middle - 1
          elif arr[middle] > val:
              end = middle - 1    
          else:
              start = middle + 1
      return answer
  def D2B(n):
      arr = []
      while (n > 0):
          temp = n; m = 0; p = 1
          while (temp):
              rem = temp % 10; temp = int(temp/10)
              if (rem != 0):
                  m += p;
              p *= 10;
          arr.append(m); n = n - m;
      return arr
  def sort2D(arr,axis):
      arr = sorted(arr, key = itemgetter(axis)); return arr
  def DD(rows,cols):
      arr = [[0 for i in range(cols)] for j in range(rows)]; return arr
  # region fastio
  
  BUFSIZE = 8192
  
  
  class FastIO(IOBase):
      newlines = 0
  
      def __init__(self, file):
          self._fd = file.fileno()
          self.buffer = BytesIO()
          self.writable = "x" in file.mode or "r" not in file.mode
          self.write = self.buffer.write if self.writable else None
  
      def read(self):
          while True:
              b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
              if not b:
                  break
              ptr = self.buffer.tell()
              self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
          self.newlines = 0
          return self.buffer.read()
  
      def readline(self):
          while self.newlines == 0:
              b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
              self.newlines = b.count(b"\n") + (not b)
              ptr = self.buffer.tell()
              self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
          self.newlines -= 1
          return self.buffer.readline()
  
      def flush(self):
          if self.writable:
              os.write(self._fd, self.buffer.getvalue())
              self.buffer.truncate(0), self.buffer.seek(0)
  
  class IOWrapper(IOBase):
      def __init__(self, file):
          self.buffer = FastIO(file)
          self.flush = self.buffer.flush
          self.writable = self.buffer.writable
          self.write = lambda s: self.buffer.write(s.encode("ascii"))
          self.read = lambda: self.buffer.read().decode("ascii")
          self.readline = lambda: self.buffer.readline().decode("ascii")
  
  sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
  input = lambda: sys.stdin.readline().rstrip("\r\n")
  
  # endregion
  if(os.path.exists('input.txt')):
      sys.stdin = open("input.txt","r")
      sys.stdout = open("output.txt","w")
  
  f = 1
  
  if __name__ == "__main__":
      if f == 1:
          t = int(input())
          while(t):
              solve(); t -= 1
      else: solve()