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.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.StringTokenizer;
  
  public class _1554_A {
  
      private static final FastScanner in = new FastScanner();
      private static final PrintWriter out = new PrintWriter(System.out);
      private static final PrintWriter err = new PrintWriter(System.err);
  
      public static void solve() {
          int n = in.nextInt();
          long[] arr = in.nextLongArray(n);
          long max = arr[0] * arr[1];
          for (int i = 1; i < n - 1; i++) {
              if (arr[i] * arr[i+1] > max) {
                  max = arr[i] * arr[i+1];
              }
          }
  
          out.println(max);
      }
  
      // Boilerplate
      public static void main(String[] args) {
          int t = in.nextInt();
          while (t-- > 0) {
              solve();
          }
  
          err.close();
          out.close();
      }
  
      @SuppressWarnings("unused")
      static class FastScanner {
  
          StringTokenizer tok = new StringTokenizer("");
          BufferedReader in;
  
          FastScanner() {
              in = new BufferedReader(new InputStreamReader(System.in));
          }
  
          String next() {
              while (!tok.hasMoreElements()) {
                  try {
                      tok = new StringTokenizer(in.readLine());
                  } catch (IOException e) {
                      throw new RuntimeException(e);
                  }
              }
  
              return tok.nextToken();
          }
  
          String nextLine() {
              String line;
              try {
                  line = in.readLine();
              } catch (IOException e) {
                  throw new RuntimeException(e);
              }
              return line;
          }
  
          int nextInt() {
              return Integer.parseInt(next());
          }
  
          int[] nextIntArray(int n) {
              int[] arr = new int[n];
              for (int i = 0; i < n; i++) {
                  arr[i] = nextInt();
              }
              return arr;
          }
  
          List<Integer> nextIntegerList(int n) {
              ArrayList<Integer> list = new ArrayList<>(n);
              for (int i = 0; i < n; i++) {
                  list.add(nextInt());
              }
              return list;
          }
  
          long nextLong() {
              return Long.parseLong(next());
          }
  
          long[] nextLongArray(int n) {
              long[] arr = new long[n];
              for (int i = 0; i < n; i++) {
                  arr[i] = nextLong();
              }
              return arr;
          }
  
          List<Long> nextLongList(int n) {
              ArrayList<Long> list = new ArrayList<>(n);
              for (int i = 0; i < n; i++) {
                  list.add(nextLong());
              }
              return list;
          }
  
          ArrayList<Integer>[] nextGraph(int n, int m) {
              @SuppressWarnings("unchecked")
              ArrayList<Integer>[] adj = (ArrayList<Integer>[]) new ArrayList[n];
  
              for (int i = 0; i < n; i++) {
                  adj[i] = new ArrayList<>();
              }
  
              for (int i = 0; i < m; i++) {
                  int v = nextInt();
                  int t = nextInt();
                  adj[v - 1].add(t - 1);
                  adj[t - 1].add(v - 1);
              }
  
              return adj;
          }
      }
  }