#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  double x, r1 = 0, p1 = 0, p2 = 999999999999, a, b;
  cin >> n;
  while (n--) {
    cin >> x;
    r1 = max(r1, x);
  }
  cin >> n;
  while (n--) {
    cin >> x;
    p1 = max(p1, x);
  }
  cin >> n;
  while (n--) {
    cin >> x;
    p2 = min(p2, x);
  }
  cin >> a >> b;
  x = b * p1;
  double up = x * r1 * r1, down = a * p2 + x;
  cout << setprecision(10) << sqrt(up / down);
}
