#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, x, a, b, r1 = 0, p1 = 0, p2 = 5001;
  for (scanf("%d", &n); n--; r1 = max(r1, x)) scanf("%d", &x);
  for (scanf("%d", &n); n--; p1 = max(p1, x)) scanf("%d", &x);
  for (scanf("%d", &n); n--; p2 = min(p2, x)) scanf("%d", &x);
  scanf("%d%d", &a, &b);
  printf("%.12f\n", sqrt(r1 * r1 * 1.0 * p1 * b / (a * p2 + p1 * b)));
}
