#include <bits/stdc++.h>
using namespace std;
int main() {
  unsigned long long n, m, k, A, B;
  cin >> n;
  int x[n];
  for (int i = 0; i < n; i++) cin >> x[i];
  cin >> m;
  int y[m];
  for (int i = 0; i < m; i++) cin >> y[i];
  cin >> k;
  int z[k];
  for (int i = 0; i < k; i++) cin >> z[i];
  cin >> A >> B;
  sort(x, x + n);
  sort(y, y + m);
  sort(z, z + k);
  unsigned long long r1 = x[n - 1];
  unsigned long long p1 = y[m - 1];
  unsigned long long p2 = z[0];
  unsigned long long B1 = B * r1 * r1 * p1;
  unsigned long long B2 = (A * p2 + B * p1);
  long double r2 = sqrt((double)(B1) / B2);
  cout << setprecision(20) << fixed << r2;
}
