#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, k;
  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];
  cin >> k;
  int z[k];
  for (int i = 0; i < k; i++) cin >> z[i];
  int A, B;
  cin >> A >> B;
  long double ratio = (double)A / B;
  sort(x, x + n);
  sort(y, y + m);
  sort(z, z + k);
  int i = n - 1;
  int j = m - 1;
  int r = 0;
  long double r2 =
      (long double)(x[i] * x[i]) / (1.00 + ratio * z[r] / (long double)y[j]);
  r2 = sqrt(r2);
  cout.precision(13);
  cout << r2 << endl;
  return 0;
}
