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: //package com.amoghghadge.compProgramming.CodeforcesUnder1100;
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.StringTokenizer;
  
  public class Cherry {
  
      public static void main(String[] args) {
          
          FastReader in = new FastReader();
          StringBuffer sb = new StringBuffer();
  
          int t = in.nextInt();
          
          while (t > 0) {
  
              int n = in.nextInt();
              ArrayList<Long> nums = new ArrayList<Long>();
              long maxValue = Long.MIN_VALUE;
  
              for (int i = 0; i < n; i++) {
  
                  nums.add(in.nextLong());
  
              }
  
              for (int i = 0; i < n - 1; i++) {
  
                  if (nums.get(i) * nums.get(i + 1) > maxValue) {
  
                      maxValue = nums.get(i) * nums.get(i + 1);
  
                  }
  
              }
  
              sb.append(maxValue + "\n");
  
              t--;
  
          }
  
          System.out.println(sb);
  
      }
  
      static int gcd (int a, int b) {
          
          if (b == 0) {
  
              return a;
  
          } else {
  
              return gcd(b, a % b);
  
          }
  
      }
   
      static long gcd (long a, long b) {
          
          if (b == 0) {
  
              return a;
  
          } else {
  
              return gcd(b, a % b);
  
          }
  
      }
   
      static long lcm (int a, int b) {
  
          return (long) a / gcd(a, b) * b;
  
      }
   
      static long lcm (long a, long b) {
  
          return a / gcd(a, b) * b;
  
      }
  
      public static int search (int l, int r, int[] a, int key) {
  
          while (l <= r) {
  
              int middle = ((r - l) / 2) + l;
  
              if (a[middle] == key) {
  
                  return middle;
  
              } else if (a[middle] < key) {
  
                  l = middle + 1;
  
              } else {
  
                  r = middle - 1;
  
              }
  
          }
  
          return -1;
  
      }
  
      public static void sort (int[] a) {
  
  		ArrayList<Integer> l=new ArrayList<>();
  		for (int i:a) l.add(i);
  		Collections.sort(l);
  		for (int i=0; i<a.length; i++) a[i]=l.get(i);
          
  	}
  
      public static void sort (long[] a) {
  
  		ArrayList<Long> l=new ArrayList<>();
  		for (long i:a) l.add(i);
  		Collections.sort(l);
  		for (int i=0; i<a.length; i++) a[i]=l.get(i);
  
  	}
  
      public static class FastReader {
  
          BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
          StringTokenizer st;
  
          public String next() {
  
              while (st == null || !st.hasMoreElements()) {
  
                  try {
  
                      st = new StringTokenizer(br.readLine());
  
                  } catch (IOException e) {
  
                      e.printStackTrace();
  
                  }
  
              }
  
              return st.nextToken();
  
          }
  
          public int nextInt() {
  
              return Integer.parseInt(next());
  
          }
  
          public long nextLong() {
  
              return Long.parseLong(next());
  
          }
  
          public double nextDouble() {
  
              return Double.parseDouble(next());
  
          }
  
          public String nextLine() {
  
              String str = "";
  
              try {
  
                  str = br.readLine();
  
              } catch (IOException e) {
  
                  e.printStackTrace();
  
              }
  
              return str;
  
          }
  
          public int[] readArray(int n) {
  
  			int[] a = new int[n];
  
  			for (int i = 0; i < n; i++) {
                  
                  a[i] = nextInt();
  			
              }
  
              return a;
  
  		}
  
          public long[] readArrayLong(long n) {
  
  			long[] a = new long[(int) n];
  
  			for (int i = 0; i < n; i++) {
                  
                  a[i] = nextLong();
  			
              }
  
              return a;
  
  		}
  
      }
  
  }