#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, k;
  long long r = -1, p1 = -1, p2 = 999999999;
  long long a, b;
  cin >> n;
  while (n--) {
    cin >> a;
    r = max(r, a);
  }
  cin >> m;
  while (m--) {
    cin >> a;
    p1 = max(p1, a);
  }
  cin >> k;
  while (k--) {
    cin >> a;
    p2 = min(p2, a);
  }
  cin >> a >> b;
  double r2 = sqrt((double)(b * p1 * r * r) / (double)(a * p2 + b * p1));
  cout << setprecision(10) << r2 << endl;
  return 0;
}
