#include <bits/stdc++.h>
using namespace std;
const int inf = 1000000000;
const int MOD = 1000000007;
double r1[5005], p1[5005], p2[5005];
int main() {
  int n;
  cin >> n;
  for (int i = 1; i <= n; ++i) cin >> r1[i];
  sort(r1 + 1, r1 + n + 1);
  int m;
  cin >> m;
  for (int i = 1; i <= m; ++i) cin >> p1[i];
  sort(p1 + 1, p1 + m + 1);
  int k;
  cin >> k;
  for (int i = 1; i <= k; ++i) cin >> p2[i];
  sort(p2 + 1, p2 + k + 1);
  double A, B;
  cin >> A >> B;
  double ans = 0.0, P2 = p2[1];
  for (int i = 1; i <= n; ++i)
    for (int j = 1; j <= m; ++j) {
      double cur = sqrt((r1[i] * r1[i] * p1[j] * B) / (A * P2 + B * p1[j]));
      if (cur < r1[i]) ans = max(ans, cur);
    }
  printf("%.6f\n", ans);
}
