#include <bits/stdc++.h>
using namespace std;
int n, m, k;
int main() {
  float mxa = 0, mxb = 0, mnc = 5000, a, b, c, x, y;
  cin >> n;
  for (int i = 0; i < n; ++i) {
    cin >> a;
    if (a > mxa) mxa = a;
  }
  cin >> m;
  for (int j = 0; j < m; ++j) {
    cin >> b;
    if (b > mxb) mxb = b;
  }
  cin >> k;
  for (int j = 0; j < k; ++j) {
    cin >> c;
    if (c < mnc) mnc = c;
  }
  float s;
  cin >> x >> y;
  s = mxa * sqrt(mxb * y / (x * mnc + y * mxb));
  cout.setf(ios::fixed);
  cout.precision(6);
  cout << s;
  return 0;
}
