#include <bits/stdc++.h>
using namespace std;
int main() {
  int numR = 0;
  int numP1 = 0;
  int numP2 = 0;
  int A = 0;
  int B = 0;
  vector<int> arrR;
  vector<int> arrP1;
  vector<int> arrP2;
  scanf("%d", &numR);
  while (numR-- > 0) {
    int n = 0;
    scanf("%d", &n);
    arrR.push_back(n);
  }
  sort(arrR.begin(), arrR.end());
  scanf("%d", &numP1);
  while (numP1-- > 0) {
    int n = 0;
    scanf("%d", &n);
    arrP1.push_back(n);
  }
  sort(arrP1.begin(), arrP1.end());
  scanf("%d", &numP2);
  while (numP2-- > 0) {
    int n = 0;
    scanf("%d", &n);
    arrP2.push_back(n);
  }
  sort(arrP2.begin(), arrP2.end());
  scanf("%d %d", &A, &B);
  double r = (double)(arrR[arrR.size() - 1]);
  double p1 = (double)(arrP1[arrP1.size() - 1]);
  double p2 = (double)(arrP2[0]);
  double ret =
      sqrt(r * r * p1 * (double)(B) / (p1 * (double)(B) + p2 * (double)(A)));
  printf("%lf\n", ret);
  return 0;
}
