#include <bits/stdc++.h>
using namespace std;
int r1[5000 + 10], p1[5000 + 10], p2[5000 + 10];
int n, m, k;
double solve(int A, int B) {
  sort(r1, r1 + n);
  sort(p1, p1 + m);
  sort(p2, p2 + k);
  double res = 2147483647;
  for (int i = 0; i < m; i++)
    for (int j = 0; j < k; j++)
      if (p1[i]) res = min(res, (double)p2[j] / p1[i]);
  return sqrt((double)B * r1[n - 1] * r1[n - 1] / (A * res + B));
}
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) cin >> r1[i];
  cin >> m;
  for (int i = 0; i < m; i++) cin >> p1[i];
  cin >> k;
  for (int i = 0; i < k; i++) cin >> p2[i];
  int A, B;
  cin >> A >> B;
  printf("%.12lf\n", solve(A, B));
  return 0;
}
