#include <bits/stdc++.h>
using namespace std;
int main() {
  vector<int> x, y, z;
  int A, B, n, m, k, f, max_r1 = 0, max_p1 = 0, min_p2 = 10000;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> f;
    x.push_back(f);
    max_r1 = max(max_r1, f);
  }
  cin >> m;
  for (int i = 0; i < m; i++) {
    cin >> f;
    y.push_back(f);
    max_p1 = max(max_p1, f);
  }
  cin >> k;
  for (int i = 0; i < k; i++) {
    cin >> f;
    z.push_back(f);
    min_p2 = min(min_p2, f);
  }
  cin >> A >> B;
  double r2 = 0, den = A * min_p2, num = max_r1 * max_r1 * B;
  for (vector<int>::iterator j = y.begin(); j != y.end(); j++)
    r2 = max(r2, sqrt((*j) * num / (den + (*j) * B)));
  r2 = max_r1 / sqrt((A * min_p2) / double(max_p1 * B) + 1);
  printf("%.16lf\n", r2);
  return 0;
}
