#include <bits/stdc++.h>
using namespace std;
const int INF = 1000000007;
int main() {
  int n;
  cin >> n;
  int R1[n];
  for (int i = 0; i < n; i++) {
    cin >> R1[i];
  }
  sort(R1, R1 + n);
  int m;
  cin >> m;
  int P1[m];
  for (int i = 0; i < m; i++) {
    cin >> P1[i];
  }
  sort(P1, P1 + m);
  int k;
  cin >> k;
  int P2[k];
  for (int i = 0; i < k; i++) {
    cin >> P2[i];
  }
  sort(P2, P2 + k);
  double a, b;
  cin >> a >> b;
  double ans = (R1[n - 1] * R1[n - 1]) /
               (((double)a / b) * ((double)P2[0] / P1[m - 1]) + 1);
  cout << setprecision(12) << sqrt(ans);
}
