#include <bits/stdc++.h>
using namespace std;
double A, B;
const int maxn = 10000;
double a[maxn], b[maxn], c[maxn];
int a1, b1, c1;
double cal(double r1, double p1, double p2) {
  return r1 * sqrt(B * p1 / (A * p2 + B * p1));
}
int main() {
  scanf("%d", &a1);
  for (int i = 0; i < a1; i++) scanf("%lf", &a[i]);
  scanf("%d", &b1);
  for (int i = 0; i < b1; i++) scanf("%lf", &b[i]);
  scanf("%d", &c1);
  for (int i = 0; i < c1; i++) scanf("%lf", &c[i]);
  scanf("%lf%lf", &A, &B);
  sort(a, a + a1);
  sort(b, b + b1);
  sort(c, c + c1);
  double ans = -1;
  for (int i = 0; i < b1; i++) {
    double aa = cal(a[a1 - 1], b[i], c[0]);
    if (ans == -1 || ans < aa) ans = aa;
  }
  printf("%.8lf\n", ans);
  return 0;
}
