#include <bits/stdc++.h>
using namespace std;
int x[1001], y[1001], z[1001], ans = 0;
int main() {
  int n, m, r[50001], p1[5001], p2[5001], i, j, a, b, k,
      max_p1 = 0, min_p2 = 5000, max_r = 0;
  cin >> n;
  for (i = 0; i < n; i++) cin >> r[i], max_r = max(max_r, r[i]);
  cin >> m;
  for (i = 0; i < m; i++) cin >> p1[i], max_p1 = max(p1[i], max_p1);
  cin >> k;
  for (i = 0; i < k; i++) cin >> p2[i], min_p2 = min(p2[i], min_p2);
  cin >> a >> b;
  double x = (double)a / b;
  cout.precision(10);
  cout << sqrt(max_r * max_r / (1 + x * min_p2 / max_p1));
  return 0;
}
