#include <bits/stdc++.h>
using namespace std;
double r1, x, A, B, p1, p2, ans, t, y[5002], z[5002], r2;
int n, m, k;
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> x;
    r1 = (((r1) > (x)) ? (r1) : (x));
  }
  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;
  for (int i = 1; i <= m; i++)
    for (int j = 1; j <= k; j++) {
      p1 = y[i];
      p2 = z[j];
      t = (p2 * A) / (p1 * B);
      r2 = sqrt((r1 * r1) / (t + 1));
      ans = (((ans) > (r2)) ? (ans) : (r2));
    }
  printf("%.9f\n", ans);
  return 0;
}
