#include <bits/stdc++.h>
using namespace std;
long long gcd(long long m, long long n) {
  long long r;
  while (n != 0) {
    r = m % n;
    m = n;
    n = r;
  }
  return m;
}
int main() {
  double r1 = 0, p1 = 0, p2 = 6000;
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    double a;
    cin >> a;
    r1 = max(r1, a);
  }
  cin >> n;
  for (int i = 0; i < n; i++) {
    double a;
    cin >> a;
    p1 = max(p1, a);
  }
  cin >> n;
  for (int i = 0; i < n; i++) {
    double a;
    cin >> a;
    p2 = min(p2, a);
  }
  double A, B;
  cin >> A >> B;
  double r2;
  r2 = (r1 * r1) / (((A * p2) / (B * p1)) + 1);
  r2 = sqrt(r2);
  printf("%0.10f\n", r2);
  return 0;
}
