#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, m, a, i, b;
  double p1, p2, r1;
  cin >> n;
  int arr1[n];
  for (i = 0; i < n; i++) {
    cin >> arr1[i];
  }
  sort(arr1, arr1 + n);
  r1 = arr1[n - 1];
  cin >> m;
  int arr2[m];
  for (i = 0; i < m; i++) {
    cin >> arr2[i];
  }
  sort(arr2, arr2 + m);
  p1 = arr2[m - 1];
  cin >> k;
  int arr3[k];
  for (i = 0; i < k; i++) {
    cin >> arr3[i];
  }
  sort(arr3, arr3 + k);
  p2 = arr3[0];
  cin >> a >> b;
  double r2;
  r2 = (double)(b * p1 * r1 * r1) / (p2 * a + b * p1);
  r2 = sqrt(r2);
  printf("%.12lf", r2);
  return 0;
}
