#include <bits/stdc++.h>
using namespace std;
int n, Pn;
double P[100000];
int main() {
  scanf("%d", &n);
  double r1 = -1e9, p1 = -1e9, p2 = 1e9;
  for (int i = 0; i < n; ++i) {
    double x;
    scanf("%lf", &x);
    r1 = max(r1, x);
  }
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) {
    double x;
    scanf("%lf", &x);
    p1 = max(p1, x);
    P[Pn++] = x;
  }
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) {
    double x;
    scanf("%lf", &x);
    p2 = min(p2, x);
  }
  double A, B;
  scanf("%lf%lf", &A, &B);
  double ans = -1e9;
  for (int i = 0; i < Pn; ++i) {
    p1 = P[i];
    ans = max(ans, (r1 * r1 * p1 * B) / (B * p1 + A * p2));
  }
  printf("%.6lf", sqrt(ans));
  return 0;
}
