#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 5005;
int A, B;
int n, m, k;
int r1[MAX_N], p1[MAX_N], p2[MAX_N];
int main() {
  cin >> n;
  for (int i = 0; i < n; ++i) cin >> r1[i];
  cin >> m;
  for (int i = 0; i < m; ++i) cin >> p1[i];
  cin >> k;
  for (int i = 0; i < k; ++i) cin >> p2[i];
  cin >> A >> B;
  sort(r1, r1 + n);
  double res = 0.0;
  for (int i = 0; i < m; ++i)
    for (int j = 0; j < k; ++j)
      res =
          max(res, sqrt(B * p1[i] / double(A * p2[j] + B * p1[i])) * r1[n - 1]);
  printf("%.6lf\n", res);
  return 0;
}
