#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-6;
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T>
void __print(const T &x) {
  int f = 0;
  cerr << '{';
  for (auto &i : x) cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
void solve() {
  long long n, i, j;
  cin >> n;
  long long x[n];
  for (i = 0; i < n; i++) {
    cin >> x[i];
  }
  long long m;
  cin >> m;
  long long y[m];
  for (i = 0; i < m; i++) {
    cin >> y[i];
  }
  long long k;
  cin >> k;
  long long z[k];
  for (i = 0; i < k; i++) {
    cin >> z[i];
  }
  long long a, b;
  sort(x, x + n);
  sort(y, y + m);
  sort(z, z + k);
  cin >> a >> b;
  double r = double(x[n - 1] * sqrt((double(b * y[m - 1])) /
                                    double(a * z[0] + b * y[m - 1])));
  cout << fixed << setprecision(18) << r << '\n';
}
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  ;
  long long t = 1;
  while (t--) solve();
}
