#include <bits/stdc++.h>
using namespace std;
double max(double a, double b) { return a > b ? a : b; }
double min(double a, double b) { return a > b ? b : a; }
double x[10101], y[10101], z[10101], A, B;
int n, m, k;
void slv() {
  double minx = -1;
  sort(x + 1, x + n + 1);
  sort(y + 1, y + m + 1);
  sort(z + 1, z + k + 1);
  double tmp = sqrt(x[n] * x[n] / (1 + ((A * z[1]) / (B * y[m]))));
  printf("%lf\n", tmp);
}
int main() {
  while (cin >> n) {
    for (int i = 1; i <= n; i++) {
      cin >> x[i];
    }
    cin >> m;
    for (int i = 1; i <= m; i++) {
      cin >> y[i];
    }
    cin >> k;
    for (int i = 1; i <= k; i++) {
      cin >> z[i];
    }
    cin >> A >> B;
    slv();
  }
}
