#include <bits/stdc++.h>
using namespace std;
int main() {
  cout.precision(8);
  cout.fixed;
  int n, m, k;
  double r1, p1, p2, a, b;
  int buf;
  cin >> n;
  r1 = 0;
  for (int i = 0; i < n; i++) {
    cin >> buf;
    if (buf > r1) r1 = buf;
  }
  cin >> m;
  p1 = 0;
  for (int i = 0; i < m; i++) {
    cin >> buf;
    if (buf > p1) p1 = buf;
  }
  cin >> k;
  p2 = 5000;
  for (int i = 0; i < k; i++) {
    cin >> buf;
    if (buf < p2) p2 = buf;
  }
  cin >> a;
  cin >> b;
  double r2 = r1 / sqrt((a * p2) / (p1 * b) + 1);
  cout << r2 << endl;
  return 0;
}
