#include <bits/stdc++.h>   using namespace std;   int n;   long long a[305], Lcm;   long long sol(long long x) {     long long cnt = 0;     for (long long i = 2; i * i <= x; i++) {       if (x % i == 0) {         cnt += 2;         if (i * i == x) cnt--;       }     }     return cnt;   }   int main() {     int T;     cin >> T;     while (T--) {       int ok = 1;       scanf( %d , &n);       for (int i = 0; i < n; i++) scanf( %lld , &a[i]);       sort(a, a + n);       if (n == 1)         Lcm = a[0] * a[0];       else         Lcm = a[0] * a[n - 1];       for (int i = 1; i < (n + 1) / 2; i++) {         if (a[i] * a[n - 1 - i] != Lcm) {           ok = 0;           break;         }       }       if (ok && sol(Lcm) == n)         printf( %lld n , Lcm);       else         puts( -1 );     }   }   