#include <bits/stdc++.h>
using namespace std;
const int oo = (int)1e9;
const long long ool = (long long)1e17;
const double eps = 1e-7;
const double PI = acos(-1.0);
int main() {
  int a;
  double p1 = 0, p2 = oo, r1 = 0;
  cin >> a;
  if (cin.fail()) return 0;
  for (int i = 0; i < a; i++) {
    int x;
    cin >> x;
    r1 = (((r1) > (x)) ? (r1) : (x));
  }
  cin >> a;
  for (int i = 0; i < a; i++) {
    int x;
    cin >> x;
    p1 = (((p1) > (x)) ? (p1) : (x));
  }
  cin >> a;
  for (int i = 0; i < a; i++) {
    int x;
    cin >> x;
    p2 = (((p2) < (x)) ? (p2) : (x));
  }
  double A, B;
  cin >> A >> B;
  double r2 = sqrt((p1 * B * r1 * r1) / (A * p2 + B * p1));
  printf("%.9lf\n", r2);
  return 0;
}
