#include <bits/stdc++.h>
using namespace std;
double a, b, r1, p1, p2 = 10000, n, m, k;
int main() {
  cin >> n;
  while (n--) {
    double rad;
    cin >> rad;
    r1 = max(r1, rad);
  }
  cin >> m;
  while (m--) {
    double den1;
    cin >> den1;
    p1 = max(p1, den1);
  }
  cin >> k;
  while (k--) {
    double den2;
    cin >> den2;
    p2 = min(p2, den2);
  }
  cin >> a >> b;
  printf("%.8f\n", r1 * sqrt((b * p1) / (b * p1 + a * p2)));
}
