#include <bits/stdc++.h>
using namespace std;
int main() {
  int X1[5005], P1[5005], P2[5005], A, B, p, n, m;
  scanf("%d", &p);
  for (int i = 0; i < p; i++) {
    scanf("%d", &X1[i]);
  }
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d", &P1[i]);
  }
  scanf("%d", &m);
  for (int i = 0; i < m; i++) {
    scanf("%d", &P2[i]);
  }
  scanf("%d%d", &A, &B);
  sort(X1, X1 + p);
  sort(P1, P1 + n);
  sort(P2, P2 + m);
  double a = B * P1[n - 1];
  a = sqrt(a);
  a = a * X1[p - 1];
  double b = A * P2[0] + B * P1[n - 1];
  b = sqrt(b);
  double r = a / b;
  r = printf("%.12f", r);
  return 0;
}
