#include <bits/stdc++.h>
using namespace std;
int n, A, B, maxR1 = 0, maxP1 = 0, minP2 = 5001;
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    int x;
    cin >> x;
    if (x > maxR1) maxR1 = x;
  }
  cin >> n;
  for (int i = 0; i < n; i++) {
    int y;
    cin >> y;
    if (y > maxP1) maxP1 = y;
  }
  cin >> n;
  for (int i = 0; i < n; i++) {
    int z;
    cin >> z;
    if (z < minP2) minP2 = z;
  }
  cin >> A >> B;
  double ans = maxR1 * sqrt((double)(B * maxP1) / (A * minP2 + B * maxP1));
  cout << fixed << setprecision(9) << ans;
  return 0;
}
