#include <bits/stdc++.h>
using namespace std;
double rr1[5010];
double pp1[5010];
double pp2[5010];
int main() {
  int num1, num2, num3;
  scanf("%d", &num1);
  double br1 = 0;
  while (num1--) {
    double tt;
    scanf("%lf", &tt);
    br1 = max(br1, tt);
  }
  scanf("%d", &num1);
  double bp1 = 0;
  while (num1--) {
    double tt;
    scanf("%lf", &tt);
    bp1 = max(bp1, tt);
  }
  scanf("%d", &num1);
  double bp2 = 1e6;
  while (num1--) {
    double tt;
    scanf("%lf", &tt);
    if (tt != 0) bp2 = min(bp2, tt);
  }
  double a, b;
  scanf("%lf%lf", &a, &b);
  double r2 = sqrt(br1 * br1 / (1.0 + bp2 * a / bp1 / b));
  printf("%.6lf\n", r2);
  return 0;
}
