#include <bits/stdc++.h>
using namespace std;
int a[5005];
int main(int argc, char** argv) {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  sort(a, a + n);
  double r1 = a[n - 1];
  int m;
  cin >> m;
  for (int i = 0; i < m; i++) {
    cin >> a[i];
  }
  sort(a, a + m);
  double p1 = a[m - 1];
  int k;
  cin >> k;
  for (int i = 0; i < k; i++) {
    cin >> a[i];
  }
  sort(a, a + k);
  double p2 = a[0];
  double A, B;
  cin >> A >> B;
  double ans = ((double)B * p1 * r1 * r1) / ((double)A * p2 + B * p1);
  cout << fixed << setprecision(12) << sqrt(ans);
  return 0;
}
