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.*;
  
  public class CF735A {
  	public static void solve(IO io) {
  
  		int n = io.getInt();
  		
  		long [] lol = new long[n];
  		
  		for (int i = 0; i < n; i++ ) {
  			lol[i] = io.getLong();
  		}
  		
  		long max = 0;
  		for (int i = 0; i < n - 1; i++) {
  			if (lol[i]*lol[i+1] > max) {
  				max = lol[i]*lol[i+1];
  			}
  			
  		}
  		System.out.println(max);
  	}
  
  	public static void main(String[] args) {
  		IO io = new IO();
  		int t = io.getInt();
  		for (int testIndex = 0; testIndex < t; testIndex++) {
  			solve(io);
  		}
  		io.close();
  	}
  
  	static class IO extends PrintWriter {
  
  		public IO() {
  			super(new BufferedOutputStream(System.out));
  			r = new BufferedReader(new InputStreamReader(System.in));
  		}
  
  		public IO(InputStream i) {
  			super(new BufferedOutputStream(System.out));
  			r = new BufferedReader(new InputStreamReader(i));
  		}
  
  		public IO(InputStream i, OutputStream o) {
  			super(new BufferedOutputStream(o));
  			r = new BufferedReader(new InputStreamReader(i));
  		}
  
  		public boolean hasMoreTokens() {
  			return peekToken() != null;
  		}
  
  		public int getInt() {
  			return Integer.parseInt(nextToken());
  		}
  
  		public double getDouble() {
  			return Double.parseDouble(nextToken());
  		}
  
  		public long getLong() {
  			return Long.parseLong(nextToken());
  		}
  
  		public String getWord() {
  			return nextToken();
  		}
  
  		private BufferedReader r;
  		private String line;
  		private StringTokenizer st;
  		private String token;
  
  		private String peekToken() {
  			if (token == null)
  				try {
  					while (st == null || !st.hasMoreTokens()) {
  						line = r.readLine();
  						if (line == null)
  							return null;
  						st = new StringTokenizer(line);
  					}
  					token = st.nextToken();
  				} catch (IOException e) {
  				}
  			return token;
  		}
  
  		private String nextToken() {
  			String ans = peekToken();
  			token = null;
  			return ans;
  		}
  	}
  }
  