#include <bits/stdc++.h>
using namespace std;
int main() {
  float r1, p1, p2;
  r1 = p1 = INT_MIN;
  p2 = INT_MAX;
  int n;
  cin >> n;
  while (n--) {
    float temp;
    cin >> temp;
    r1 = max(temp, r1);
  }
  cin >> n;
  while (n--) {
    float temp;
    cin >> temp;
    p1 = max(temp, p1);
  }
  cin >> n;
  while (n--) {
    float temp;
    cin >> temp;
    p2 = min(temp, p2);
  }
  float a, b;
  cin >> a >> b;
  float r2 = r1 * (sqrt((float)(b * p1) / (a * p2 + b * p1)));
  cout << fixed << setprecision(12) << r2;
  return 0;
}
