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 java.math.BigInteger;
  import java.util.*;
  import java.io.*;
  
  public class A_Cherry {
      public static void main (String[] args) {
          FastReader scan = new FastReader();
          int t = scan.nextInt();
          while (t-- > 0) {
              int n = scan.nextInt();
              int[] arr = new int[n];
              inputArray(arr, n, scan);
              long ans = (long)arr[0]*arr[1];
              for (int i=1; i<n-1; i++) {
                  ans = Math.max(ans, (long)arr[i]*arr[i+1]);
              }
              System.out.println(ans);
          }
      }
      public static void inputArray (int[] arr, int n, FastReader scan) {
          for (int i=0; i<n; i++) {
              arr[i] = scan.nextInt();
          }
      }
      public static void printArray (int[] arr) {
          for (int i=0; i<arr.length; i++) {
              System.out.print(arr[i] + " ");
          }
          System.out.println();
      }
      public static boolean isPrime (int n) {
          if (n <= 1)
              return false;
          if (n <= 3)
              return true;
          if (n % 2 == 0 || n % 3 == 0)
              return false;
          for (int i = 5; i * i <= n; i = i + 6)
              if (n % i == 0 || n % (i + 2) == 0)
                  return false;
          return true;
      }
      public static int gcd (int a, int b) {
          BigInteger a1 = BigInteger.valueOf(a);
          BigInteger b1 = BigInteger.valueOf(b);
          return a1.gcd(b1).intValue();
      }
      public static int numberOfDigitsInNumber (int n) {
          return (int)Math.floor(Math.log10(n)) + 1;
      }
      public static boolean isPowerOfTwo (int x) {
          return x!=0 && ((x&(x-1)) == 0);   
      }
      public static String toBinaryString (int n) {
          return Integer.toString(n, 2);
          // for other bases change 2 to other bases
      }
      static class FastReader {
          BufferedReader br;
          StringTokenizer st;
   
          public FastReader()
          {
              br = new BufferedReader(
                  new InputStreamReader(System.in));
          }
   
          String next()
          {
              while (st == null || !st.hasMoreElements()) {
                  try {
                      st = new StringTokenizer(br.readLine());
                  }
                  catch (IOException e) {
                      e.printStackTrace();
                  }
              }
              return st.nextToken();
          }
   
          int nextInt() { return Integer.parseInt(next()); }
   
          long nextLong() { return Long.parseLong(next()); }
   
          double nextDouble()
          {
              return Double.parseDouble(next());
          }
   
          String nextLine()
          {
              String str = "";
              try {
                  str = br.readLine();
              }
              catch (IOException e) {
                  e.printStackTrace();
              }
              return str;
          }
      }
  }
  
  // For IO using Files
  // public static void main throws IOException
  // BufferedReader br = new BufferedReader(new FileReader("input.txt"));
  // PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter("output.txt")));
  // String st[]=br.readLine().split(" ");
  // int n=Integer.parseInt(st[0]);
  // int m=Integer.parseInt(st[1]);
  // at the end
  // br.close(); pw.close();
  // for printing pw.println(), pw.print(), etc...
  // for arrays : int arr[] = Arrays.stream(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();