#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  scanf("%d", &n);
  int x[n];
  for (int i = 0; i < n; ++i) scanf("%d", x + i);
  int m;
  scanf("%d", &m);
  int y[m];
  for (int i = 0; i < m; ++i) scanf("%d", y + i);
  int k;
  scanf("%d", &k);
  int z[k];
  for (int i = 0; i < k; ++i) scanf("%d", z + i);
  int a, b;
  scanf("%d%d", &a, &b);
  long long r1 = 0, p1, p2 = INT_MAX;
  for (int i = 0; i < n; ++i) r1 = max((long long)x[i], r1);
  for (int l = 0; l < k; ++l) p2 = min((long long)z[l], p2);
  double ans = 0, q;
  for (int j = 0; j < m; ++j) {
    p1 = y[j];
    q = sqrt(double(r1 * r1 * p1 * b) / (a * p2 + b * p1));
    if (ans + 1e-8 < q) ans = q;
  }
  printf("%.9lf\n", ans);
  return 0;
}
