#include <bits/stdc++.h>
using namespace std;
int n, m, k;
double A, B, x;
double xx[5001], yy[5001], zz[5001];
double sol = 0.0;
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%lf", &xx[i]);
  }
  scanf("%d", &m);
  for (int i = 0; i < m; i++) {
    scanf("%lf", &yy[i]);
  }
  scanf("%d", &k);
  for (int i = 0; i < k; i++) {
    scanf("%lf", &zz[i]);
  }
  scanf("%lf%lf", &A, &B);
  x = A / B;
  sort(xx, xx + n);
  sort(zz, zz + k);
  for (int i = 0; i < m; i++) {
    double curr = sqrt((yy[i] * xx[n - 1] * xx[n - 1]) / (x * zz[0] + yy[i]));
    if (curr > sol) sol = curr;
  }
  printf("%.10lf\n", sol);
  return 0;
}
