#include <bits/stdc++.h>
using namespace std;
int a[55], b[55];
int main() {
  double r, p1, p2, a, b, s;
  int n;
  cin >> n;
  r = 0.0;
  for (int i = 1; i <= n; i++) {
    cin >> s;
    r = max(r, s);
  }
  cin >> n;
  p1 = 0.0;
  for (int i = 1; i <= n; i++) {
    cin >> s;
    p1 = max(p1, s);
  }
  cin >> n;
  p2 = 1e100;
  for (int i = 1; i <= n; i++) {
    cin >> s;
    p2 = min(p2, s);
  }
  cin >> a >> b;
  printf("%.10f", sqrt(r * r / (a * p2 / b / p1 + 1)));
  return 0;
}
