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 Main{
  	static void main() throws Exception{
  	    int n=sc.nextInt();
  		long ans=0;
  		long prev=sc.nextInt();
  		for(int i=1;i<n;i++){
  		    long cur=sc.nextInt();
  		    ans=Math.max(ans,prev*cur);
  		    prev=cur;
  		}
  		pw.println(ans);
  	}
  	public static void main(String[] args) throws Exception{
  		sc=new MScanner(System.in);
  		pw = new PrintWriter(System.out);
  		int tc=1;
          tc=sc.nextInt();
  		for(int i=1;i<=tc;i++) {
  //			pw.printf("Case #%d: ", i);
  			main();
  		}
  		pw.flush();
  	}
  	static PrintWriter pw;
  	static MScanner sc;
  	static class MScanner {
  		StringTokenizer st;
  		BufferedReader br;
  		public MScanner(InputStream system) {
  			br = new BufferedReader(new InputStreamReader(system));
  		}
  	 
  		public MScanner(String file) throws Exception {
  			br = new BufferedReader(new FileReader(file));
  		}
  	 
  		public String next() throws IOException {
  			while (st == null || !st.hasMoreTokens())
  				st = new StringTokenizer(br.readLine());
  			return st.nextToken();
  		}
  		public int[] intArr(int n) throws IOException {
  	        int[]in=new int[n];for(int i=0;i<n;i++)in[i]=nextInt();
  	        return in;
  		}
  		public long[] longArr(int n) throws IOException {
  	        long[]in=new long[n];for(int i=0;i<n;i++)in[i]=nextLong();
  	        return in;
  		}
  		public int[] intSortedArr(int n) throws IOException {
  	        int[]in=new int[n];for(int i=0;i<n;i++)in[i]=nextInt();
  	        shuffle(in);
  	        Arrays.sort(in);
  	        return in;
  		}
  		public long[] longSortedArr(int n) throws IOException {
  	        long[]in=new long[n];for(int i=0;i<n;i++)in[i]=nextLong();
  	        shuffle(in);
  	        Arrays.sort(in);
  	        return in;
  		}
  		public Integer[] IntegerArr(int n) throws IOException {
  	        Integer[]in=new Integer[n];for(int i=0;i<n;i++)in[i]=nextInt();
  	        return in;
  		}
  		public Long[] LongArr(int n) throws IOException {
  	        Long[]in=new Long[n];for(int i=0;i<n;i++)in[i]=nextLong();
  	        return in;
  		}
  		public String nextLine() throws IOException {
  			return br.readLine();
  		}
  	 
  		public int nextInt() throws IOException {
  			return Integer.parseInt(next());
  		}
  	 
  		public double nextDouble() throws IOException {
  			return Double.parseDouble(next());
  		}
  	 
  		public char nextChar() throws IOException {
  			return next().charAt(0);
  		}
  	 
  		public long nextLong() throws IOException {
  			return Long.parseLong(next());
  		}
  	 
  		public boolean ready() throws IOException {
  			return br.ready();
  		}
  	 
  		public void waitForInput() throws InterruptedException {
  			Thread.sleep(3000);
  		}
  		
  	}
  	static void dbg(int[]in) {
  		System.out.println(Arrays.toString(in));
  	}
  	static void dbg(long[]in) {
  		System.out.println(Arrays.toString(in));
  	}
  	static void sort(int[]in) {
  		shuffle(in);
  		Arrays.sort(in);
  	}
  	static void sort(long[]in) {
  		shuffle(in);
  		Arrays.sort(in);
  	}
  	static void shuffle(int[]in) {
  		for(int i=0;i<in.length;i++) {
  			int idx=(int)(Math.random()*in.length);
  			int tmp=in[i];
  			in[i]=in[idx];
  			in[idx]=tmp;
  		}
  	}
  	static void shuffle(long[]in) {
  		for(int i=0;i<in.length;i++) {
  			int idx=(int)(Math.random()*in.length);
  			long tmp=in[i];
  			in[i]=in[idx];
  			in[idx]=tmp;
  		}
  	}
  }