#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  vector<int> v;
  vector<int> w;
  vector<int> x;
  for (int i = 0; i < n; i++) {
    int q;
    cin >> q;
    v.push_back(q);
  }
  int m;
  cin >> m;
  for (int i = 0; i < m; i++) {
    int q;
    cin >> q;
    w.push_back(q);
  }
  int k;
  cin >> k;
  for (int i = 0; i < k; i++) {
    int q;
    cin >> q;
    x.push_back(q);
  }
  int a, b;
  cin >> a >> b;
  sort(v.rbegin(), v.rend());
  sort(w.rbegin(), w.rend());
  sort(x.begin(), x.end());
  double ans = 0;
  ans = v[0] / sqrt((double)(a * x[0]) / (b * w[0]) + 1);
  cout << fixed << setprecision(12) << ans << "\n";
}
