#include <bits/stdc++.h>
using namespace std;
double r1, r2, p1, p2;
int main() {
  int n;
  double m;
  r1 = p1 = -10000;
  p2 = 10000;
  cin >> n;
  while (n--) {
    cin >> m;
    r1 = max(r1, m);
  }
  cin >> n;
  while (n--) {
    cin >> m;
    p1 = max(p1, m);
  }
  cin >> n;
  while (n--) {
    cin >> m;
    p2 = min(p2, m);
  }
  double A, B;
  cin >> A >> B;
  r2 = p1 * r1 * r1 / (p1 + A * p2 / B);
  printf("%.10lf\n", sqrt(r2));
  return 0;
}
