#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  long double r1 = 0;
  while (n--) {
    long double x;
    cin >> x;
    r1 = max(r1, x);
  }
  cerr << "!1" << endl;
  int m;
  cin >> m;
  long double p1 = 0;
  while (m--) {
    long double x;
    cin >> x;
    p1 = max(p1, x);
  }
  cerr << "!2" << endl;
  int k;
  cin >> k;
  long double p2 = ((-1u) / 2);
  while (k--) {
    long double x;
    cin >> x;
    p2 = min(p2, x);
  }
  cerr << "!3" << endl;
  long double A, B;
  cin >> A >> B;
  long double X = A / B;
  long double r2 = (r1 * r1) / (X * p2 / p1 + 1);
  r2 = sqrt(r2);
  cout << fixed << setprecision(10) << r2 << endl;
  return 0;
}
