#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n, m, k, A, B;
  cin >> n;
  int r1 = -1, p2 = 100000, p1 = -1;
  for (int(i) = 0; (i) < (n); (i)++) {
    int x;
    cin >> x;
    r1 = max(x, r1);
  }
  cin >> m;
  for (int(i) = 0; (i) < (m); (i)++) {
    int x;
    cin >> x;
    p1 = max(p1, x);
  }
  cin >> k;
  for (int(i) = 0; (i) < (k); (i)++) {
    int x;
    cin >> x;
    p2 = min(p2, x);
  }
  cin >> A >> B;
  double a = r1, b = p1, c = p2;
  double ans = (a * a * B * b) / (B * b + A * c);
  cout << fixed << setprecision(10) << sqrt(ans) << "\n";
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int t = 1;
  while (t--) {
    solve();
  }
}
