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.io.*;
  import java.util.*;
  import java.lang.*;
  import static java.lang.Math.*;
  
  // Sachin_2961 submission //
  public class Codeforces {
  
      public void solve() {
          int n = fs.nInt();
          int[]ar = new int[n];
          for(int i=0;i<n;i++){
              ar[i] = fs.nInt();
          }
          long ans = 0;
          for(int i = 0;i<n-1;i++){
              long temp = ar[i];
              temp *= ar[i+1];
              ans = max(temp,ans);
          }
          out.println(ans);
      }
      static boolean multipleTestCase = true; static FastScanner fs; static PrintWriter out;
      public void run(){
          fs = new FastScanner();
          out = new PrintWriter(System.out);
          int tc = (multipleTestCase)?fs.nInt():1;
          while (tc-->0)solve();
          out.flush();
          out.close();
      }
      public static void main(String[]args){
          try{
              new Codeforces().run();
          }catch (Exception e){
              e.printStackTrace();
          }
  
      }
      static class FastScanner {
          BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
          StringTokenizer st=new StringTokenizer("");
          String n() {
              while (!st.hasMoreTokens())
                  try {
                      st=new StringTokenizer(br.readLine());
                  } catch (IOException e) {
                      e.printStackTrace();
                  }
              return st.nextToken();
          }
          String Line()
          {
              String str = "";
              try
              {
                  str = br.readLine();
              }catch (IOException e)
              {
                  e.printStackTrace();
              }
              return str;
          }
          int nInt() {return Integer.parseInt(n()); }
          long nLong() {return Long.parseLong(n());}
          double nDouble(){return Double.parseDouble(n());}
          int[]aI(int n){
              int[]ar = new int[n];
              for(int i=0;i<n;i++)
                  ar[i] = nInt();
              return ar;
          }
      }
      public static void sort(int[] arr){
          ArrayList<Integer> ls = new ArrayList<Integer>();
          for(int x: arr)
              ls.add(x);
          Collections.sort(ls);
          for(int i=0; i < arr.length; i++)
              arr[i] = ls.get(i);
      }
  }