func_code_string: #include <bits/stdc++.h>   using namespace std;   long long f(long long x) {     int num = 0;     for (int i = 1; 1ll * i * i <= x; i++) {       if (x % i) continue;       num++;       if (1ll * i * i != x) num++;     }     return num;   }   long long solve(vector<int> v) {     int n = v.size();     long long num = 1ll * v[0] * v[n - 1];     for (int i = 1; i < n / 2 + (n % 2); i++) {       long long cur = 1ll * v[i] * v[n - i - 1];       if (cur != num) return -1;     }     if (f(num) != n + 2) return -1;     return num;   }   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     int t;     cin >> t;     while (t--) {       int n;       cin >> n;       vector<int> a(n);       for (int i = 0; i < n; i++) {         cin >> a[i];       }       sort(a.begin(), a.end());       cout << solve(a) << endl;     }     return 0;   }   