#include <bits/stdc++.h>
using namespace std;
const long double N = 1e5 + 5, inf = 1e18;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int n;
  cin >> n;
  long double x[n];
  for (int i = 0; i < n; ++i) {
    cin >> x[i];
  }
  sort(x, x + n);
  int m;
  cin >> m;
  long double y[m];
  for (int i = 0; i < m; ++i) {
    cin >> y[i];
  }
  sort(y, y + m);
  int k;
  cin >> k;
  long double z[k];
  for (int i = 0; i < k; ++i) {
    cin >> z[i];
  }
  sort(z, z + k);
  long double a, b;
  cin >> a >> b;
  cout << setprecision(9) << fixed
       << x[n - 1] * sqrt((b * y[m - 1]) / (b * y[m - 1] + a * (z[0]))) << "\n";
  return 0;
}
