#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long r1 = INT_MIN, p1 = INT_MIN, p2 = INT_MAX, a, b;
  long long n, x;
  cin >> n;
  for (long long i = 0; i < n; i++) {
    cin >> x;
    r1 = max(r1, x);
  }
  cin >> n;
  for (long long i = 0; i < n; i++) {
    cin >> x;
    p1 = max(p1, x);
  }
  cin >> n;
  for (long long i = 0; i < n; i++) {
    cin >> x;
    p2 = min(p2, x);
  }
  cin >> a >> b;
  double y = b * p1;
  double z = b * p1 + a * p2;
  double k1 = y / z;
  double r2 = r1 * sqrt(k1);
  printf("%0.12f", r2);
}
