#include <bits/stdc++.h>
using namespace std;
int toInt(string s) {
  int r = 0;
  istringstream sin(s);
  sin >> r;
  return r;
}
int POW(int b, int p) {
  int r = 1;
  for (int i = 1; i <= p; i++) r *= b;
  return r;
}
bool isVowel(char ch) {
  ch = tolower(ch);
  return ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u';
}
int BigMod(long long B, long long P, long long M) {
  long long R = 1;
  while (P > 0) {
    if (P % 2 == 1) {
      R = (R * B) % M;
    }
    P /= 2;
    B = (B * B) % M;
  }
  return (int)R;
}
long long nCr(double n, double r) {
  double ans = 1;
  if (r > n - r) r = n - r;
  for (int i = 1; i <= r; i++) {
    ans *= (n - i + 1);
    ans /= i;
  }
  return (long long)ans;
}
double r1[5000 + 7];
double p1[5000 + 7];
double p2[5000 + 7];
int main() {
  int n, m, k;
  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];
  double A, B;
  cin >> A >> B;
  sort(p1, p1 + m);
  sort(p2, p2 + k);
  double c = (p1[m - 1] * B) / (p2[0] * A);
  sort(r1, r1 + n);
  printf("%.12lf\n", r1[n - 1] * sqrt(c / (c + 1)));
  return 0;
}
