#include <iostream>
using namespace std;

int gcd(int a, int b) {
  int r = a % b;
  return r ? gcd(b, r) : b;
}

int main() {
  int n; cin >> n;
  bool flag = false;
  int res = -1;
  for (int i = 0; i < n; i++) {
    int a; cin >> a;
    if (a < 0) continue;
    if (!flag) {
      flag = true;
      res = a;
    }
    res = gcd(res, a);
  }
  cout << (flag ? res * res : res) << endl;
}