#include <bits/stdc++.h>
using namespace std;
double x[10000], y[10000], z[10000];
long n, m, k, a, b;
double r1, r2;
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> x[i];
  sort(&x[1], &x[n + 1]);
  r1 = x[n];
  cin >> m;
  for (int i = 1; i <= m; i++) cin >> y[i];
  cin >> k;
  for (int i = 1; i <= k; i++) cin >> z[i];
  cin >> a >> b;
  double r2 = 0;
  for (int i = 1; i <= m; i++)
    for (int j = 1; j <= k; j++)
      if (r2 < (y[i] * r1 * r1 * b / (a * z[j] + b * y[i]))) {
        r2 = y[i] * r1 * r1 * b / (a * z[j] + b * y[i]);
      }
  printf("%.12f\n", sqrt(r2));
}
