#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  vector<int> r(n);
  int r1 = INT_MIN;
  for (int& x : r) {
    cin >> x;
    if (x > r1) r1 = x;
  }
  int m;
  cin >> m;
  vector<int> p(m);
  int p1 = INT_MIN;
  for (int& x : p) {
    cin >> x;
    if (x > p1) p1 = x;
  }
  int k;
  cin >> k;
  vector<int> P(k);
  int p2 = INT_MAX;
  for (int& x : P) {
    cin >> x;
    if (x < p2) p2 = x;
  }
  double a, b;
  cin >> a >> b;
  double r2;
  double temp = (double)(b * p1) / (b * p1 + a * p2);
  temp = sqrt(temp);
  r2 = r1 * temp;
  cout << fixed << setprecision(12) << r2;
  return 0;
}
