#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  long double r1 = 0;
  for (int i = 0; i < n; ++i) {
    long double a;
    cin >> a;
    r1 = max(r1, a);
  }
  cin >> n;
  long double p1 = 0;
  for (int i = 0; i < n; ++i) {
    long double a;
    cin >> a;
    p1 = max(p1, a);
  }
  cin >> n;
  long double p2 = 5100;
  for (int i = 0; i < n; ++i) {
    long double a;
    cin >> a;
    p2 = min(p2, a);
  }
  long double A, B;
  cin >> A >> B;
  long double ans = r1 * sqrt(p1 * B / (p1 * B + p2 * A));
  cout << setprecision(20) << ans;
  return 0;
}
