#include <bits/stdc++.h>
int main() {
  int n, m, k;
  double r1, r2, p1, p2;
  while (~scanf("%d", &n)) {
    double tt;
    r1 = 0;
    for (int i = 0; i < n; i++) {
      scanf("%lf", &tt);
      if (tt > r1) r1 = tt;
    }
    scanf("%d", &m);
    p1 = 0;
    for (int i = 0; i < m; i++) {
      scanf("%lf", &tt);
      if (tt > p1) p1 = tt;
    }
    scanf("%d", &k);
    p2 = 5000 + 47;
    for (int i = 0; i < k; i++) {
      scanf("%lf", &tt);
      if (tt < p2) p2 = tt;
    }
    int A, B;
    scanf("%d%d", &A, &B);
    double ans = sqrt((r1 * r1 * p1 * B) / (p1 * B + p2 * A));
    printf("%lf\n", ans);
  }
  return 0;
}
