#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  using namespace std::chrono;
  double n, m, k;
  cin >> n;
  vector<double> x(n);
  double r1 = INT_MIN;
  double p1 = INT_MIN;
  double p2 = INT_MAX;
  for (double i = 0; i < n; i++) {
    cin >> x[i];
    if (x[i] > r1) r1 = x[i];
  }
  cin >> m;
  vector<double> y(m);
  for (double i = 0; i < m; i++) {
    cin >> y[i];
    if (y[i] > p1) p1 = y[i];
  }
  cin >> k;
  vector<double> z(k);
  for (double i = 0; i < k; i++) {
    cin >> z[i];
    if (z[i] < p2) p2 = z[i];
  }
  double a, b;
  cin >> a >> b;
  double ans = r1 * (sqrt((b * p1) / ((b * p1) + (a * p2))));
  printf("%.8lf", ans);
  return 0;
}
