#include <bits/stdc++.h>
using namespace std;
void fast() {
  ios::sync_with_stdio(0);
  ios_base::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
}
void file() {
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
}
int main() {
  fast();
  int ma1 = 0, ma2 = 0, ma3 = 9999999;
  int x1, x2, x3, a, b;
  cin >> x1;
  int y1, y2, y3;
  while (x1-- > 0) {
    cin >> y1;
    if (y1 > ma1) {
      ma1 = y1;
    }
  }
  cin >> x2;
  while (x2-- > 0) {
    cin >> y2;
    if (y2 > ma2) {
      ma2 = y2;
    }
  }
  cin >> x3;
  while (x3-- > 0) {
    cin >> y3;
    if (y3 < ma3) {
      ma3 = y3;
    }
  }
  cin >> a >> b;
  double sum =
      ma1 * (sqrt((b * 1.0 * ma2) / ((b * 1.0 * ma2) + (a * 1.0 * ma3))));
  cout << fixed << setprecision(6) << sum;
  return 0;
}
