#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  int i, j;
  double c, m, p, r, a, b;
  scanf("%d", &n);
  r = 0;
  for (i = 0; i < n; i++) {
    scanf("%lf", &c);
    if (c > r) r = c;
  }
  scanf("%d", &n);
  p = 0;
  for (i = 0; i < n; i++) {
    scanf("%lf", &c);
    if (c > p) p = c;
  }
  scanf("%d", &n);
  m = 50000;
  for (i = 0; i < n; i++) {
    scanf("%lf", &c);
    if (c < m) m = c;
  }
  scanf("%lf%lf", &a, &b);
  b = 1 + a / b * m / p;
  a = r / sqrt(b);
  printf("%.12lf\n", a);
  return 0;
}
