#include <bits/stdc++.h>
using namespace std;
int main() {
  double n, x, r1 = 0, p1 = 0, p2 = 100000000, A, B, r2;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> x;
    r1 = max(r1, x);
  }
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> x;
    p1 = max(p1, x);
  }
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> x;
    p2 = min(p2, x);
  }
  cin >> A >> B;
  r2 = r1 * (sqrt((B * p1) / ((p1 * B) + (A * p2))));
  printf("%.10lf\n", r2);
}
