#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m;
  cin >> n;
  int x[n];
  for (int i = 0; i < n; i++) cin >> x[i];
  cin >> m;
  int y[m];
  for (int i = 0; i < m; i++) cin >> y[i];
  int k;
  cin >> k;
  int z[k];
  for (int i = 0; i < k; i++) {
    cin >> z[i];
  }
  int a, b;
  cin >> a >> b;
  int max_r = x[0];
  for (int i = 1; i < n; i++)
    if (x[i] > max_r) max_r = x[i];
  int max_p1 = y[0];
  for (int i = 1; i < m; i++)
    if (y[i] > max_p1) max_p1 = y[i];
  int min_p2 = z[0];
  for (int i = 1; i < k; i++)
    if (z[i] < min_p2) min_p2 = z[i];
  long long nr = b * max_p1;
  long long dr = b * max_p1 + a * min_p2;
  long double ratio = (long double)nr / (long double)dr;
  ratio = sqrt(ratio);
  ratio *= (long double)max_r;
  cout.precision(12);
  cout << ratio << "\n";
  return 0;
}
