#include <bits/stdc++.h>
using namespace std;
double calculr2(int p1, int p2, int r1, int A, int B) {
  double r2 = 0;
  r2 = sqrt(((double)B * p1 * r1 * r1) / ((double)A * p2 + B * p1));
  return (r2);
}
int main() {
  int n, m, k;
  cin >> n;
  int maxr1 = 0;
  int maxp1 = 0;
  int minp2 = 99999;
  int c, v, b;
  for (int i = 0; i < n; i++) {
    cin >> c;
    if (c > maxr1) {
      maxr1 = c;
    }
  }
  cin >> m;
  for (int j = 0; j < m; j++) {
    cin >> v;
    if (v > maxp1) {
      maxp1 = v;
    }
  }
  cin >> k;
  for (int l = 0; l < k; l++) {
    cin >> b;
    if (b < minp2) {
      minp2 = b;
    }
  }
  int A, B;
  cin >> A >> B;
  double r2;
  r2 = calculr2(maxp1, minp2, maxr1, A, B);
  cout << fixed << setprecision(12) << r2 << endl;
  return 0;
}
