#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long n, m, k, A, B, a, r1 = INT_MIN, p1 = INT_MIN, p2 = INT_MAX;
  double r2;
  cin >> n;
  for (long long i = 0; i < n; i++) {
    cin >> a;
    r1 = max(r1, a);
  }
  cin >> m;
  for (long long i = 0; i < m; i++) {
    cin >> a;
    p1 = max(p1, a);
  }
  cin >> k;
  for (long long i = 0; i < k; i++) {
    cin >> a;
    p2 = min(p2, a);
  }
  cin >> A >> B;
  r2 = sqrt(double(p1 * B * r1 * r1) / double(p2 * A + p1 * B));
  printf("%.6f", r2);
  return 0;
}
