#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  int m;
  int k;
  cin >> n;
  int R1 = 0;
  for (int i = 0; i < n; i++) {
    int x;
    cin >> x;
    R1 = max(R1, x);
  }
  cin >> m;
  int P1 = 0;
  for (int i = 0; i < m; i++) {
    int x;
    cin >> x;
    P1 = max(P1, x);
  }
  cin >> k;
  int P2 = 90000;
  for (int i = 0; i < k; i++) {
    int x;
    cin >> x;
    P2 = min(P2, x);
  }
  int A, B;
  cin >> A >> B;
  cout << setprecision(15)
       << R1 * sqrt((double)(B * P1) / (double)(B * P1 + A * P2));
  return 0;
}
