#include <bits/stdc++.h>
const double pi = acos(-1);
const long long INF = 1e18 + 5;
const long long mod = 1e9 + 7, MOD = 998244353;
const int N = 2e5 + 5, M = 505;
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, m, k;
  long double a, b, mx_x = 0;
  cin >> n;
  for (int i = 0; i < n; i++) {
    long double x;
    cin >> x;
    mx_x = max(mx_x, x);
  }
  cin >> m;
  long double y[m];
  for (int i = 0; i < m; i++) cin >> y[i];
  ;
  cin >> k;
  long double z[k];
  for (int i = 0; i < k; i++) cin >> z[i];
  ;
  cin >> a >> b;
  long double ans = 0;
  for (int j = 0; j < m; j++) {
    for (int h = 0; h < k; h++) {
      long double r2 =
          sqrt((b * y[j] * pow(mx_x, 2)) / ((a * z[h]) + (b * y[j])));
      ans = max(ans, r2);
    }
  }
  cout << fixed << setprecision(12) << ans;
  return 0;
}
