#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  long long a = 0, n = 0, m = 0;
  cin >> a;
  long long r1 = 0, p1 = 0, p2 = 1000000007, b = 0;
  for (int i = 0; i < a; ++i) {
    cin >> b;
    if (r1 < b) r1 = b;
  }
  cin >> n;
  for (int i = 0; i < n; ++i) {
    cin >> b;
    if (b > p1) p1 = b;
  }
  cin >> m;
  for (int i = 0; i < m; ++i) {
    cin >> b;
    if (b < p2) p2 = b;
  }
  cin >> a >> b;
  double r2 = sqrt(((double)(b * p1 * r1 * r1)) / (b * p1 + p2 * a));
  cout << fixed << setprecision(12) << r2;
  return 0;
}
