#include <bits/stdc++.h>
using namespace std;
int main() {
  double r1, r2, p1, p2;
  double A, B;
  int n;
  scanf("%d", &n);
  double x;
  r1 = 0;
  for (int i = 0; i < n; i++) {
    scanf("%lf", &x);
    if (x > r1) r1 = x;
  }
  int m;
  scanf("%d", &m);
  p1 = 0;
  for (int i = 0; i < m; i++) {
    scanf("%lf", &x);
    if (x > p1) p1 = x;
  }
  int z;
  scanf("%d", &z);
  p2 = 5005;
  for (int i = 0; i < z; i++) {
    scanf("%lf", &x);
    if (x < p2) p2 = x;
  }
  scanf("%lf %lf", &A, &B);
  r2 = (A * p2) / (B * p1) + 1;
  r2 = r1 * r1 / r2;
  r2 = sqrt(r2);
  printf("%.12lf\n", r2);
  return 0;
}
