#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, max = 0, x, y, k, m, a, b, z;
  double r;
  cin >> n;
  for (int i = 0; n > i; i++) {
    cin >> x;
    if (x > max) {
      max = x;
    }
  }
  x = max;
  max = 0;
  cin >> m;
  for (int i = 0; m > i; i++) {
    cin >> y;
    if (y > max) {
      max = y;
    }
  }
  y = max;
  max = 5001;
  cin >> k;
  for (int i = 0; k > i; i++) {
    cin >> z;
    if (max > z) {
      max = z;
    }
  }
  z = max;
  cin >> a >> b;
  r = x * sqrt((double)(b * y) / (double)(b * y + a * z));
  cout << setprecision(15) << r;
}
