#include <bits/stdc++.h>
const long x = 1e5;
int arr[x] = {0};
using namespace std;
int main() {
  int xq;
  cin >> xq;
  for (int i = 0; i < xq; i++) cin >> arr[i];
  sort(arr, arr + xq);
  double r1 = arr[xq - 1];
  int w;
  cin >> w;
  for (int i = 0; i < w; i++) cin >> arr[i];
  sort(arr, arr + w);
  double p1 = arr[w - 1];
  int wc;
  cin >> wc;
  for (int i = 0; i < wc; i++) cin >> arr[i];
  sort(arr, arr + wc);
  double p2 = arr[0];
  int A, B;
  cin >> A;
  cin >> B;
  std::cout << std::fixed;
  std::cout << std::setprecision(12);
  cout << sqrt((p1 * B * pow(r1, 2)) / (A * p2 + B * p1));
  return 0;
}
