#include <bits/stdc++.h>   const double PI = 3.141592653589793238460;   using namespace std;   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     int t = 1;     cin >> t;     while (t--) {       long long int n;       cin >> n;       long long int a[n], i, sum = 0, maxi = -1000000000, mini = 1000000000;       for (int i = 0; i < n; i++) {         cin >> a[i];         if (a[i] > maxi)           maxi = a[i];         else if (a[i] < mini)           mini = a[i];       }       for (i = 0; i < n - 1; i++) {         long long int pro = a[i] * a[i + 1];         if (pro > sum) {           sum = pro;         }       }       cout << sum <<   n ;     }     return 0;   }   