#include <bits/stdc++.h>
using namespace std;
bool sortbysec(const pair<char, long long int> &a,
               const pair<char, long long int> &b) {
  return (a.second < b.second);
}
long long int highest2(long long int n) {
  long long int x = n;
  while (n) {
    x = n;
    n = n & (n - 1);
  }
  return x;
}
long long int power(long long int x, long long int y, long long int p) {
  long long int res = 1;
  x = x % p;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
long long int modInverse(long long int n, long long int p) {
  return power(n, p - 2, p);
}
long long int nCrModPFermat(long long int n, long long int r, long long int p) {
  if (r == 0) return 1;
  long long int fac[n + 1];
  fac[0] = 1;
  for (long long int i = 1; i <= n; i++) fac[i] = fac[i - 1] * i % p;
  return (fac[n] * modInverse(fac[r], p) % p * modInverse(fac[n - r], p) % p) %
         p;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  long long int m, q, y, n, t, p, row, k, col, x, i, j, p2, p1, mno, R,
      l = 0, r1 = 0, count = 0, net1 = 0, net2 = 0;
  cin >> n;
  long long int a[n];
  for (long long int i = 0; i < n; i++) cin >> a[i];
  cin >> m;
  long long int b[m];
  for (long long int i = 0; i < m; i++) cin >> b[i];
  cin >> k;
  long long int c[k];
  for (long long int i = 0; i < k; i++) cin >> c[i];
  long long int A, B;
  cin >> A >> B;
  sort(a, a + n);
  sort(b, b + m);
  sort(c, c + k);
  r1 = a[n - 1];
  p1 = b[m - 1];
  p2 = c[0];
  long double r2;
  r2 = B * p1 * r1 * r1;
  r2 /= (long double)(A * p2 + B * p1);
  cout << setprecision(14) << sqrt(r2);
  return 0;
}
