#include <bits/stdc++.h>
int main() {
  int i, n, a, b, f = -1, s = -1, t = 5001;
  double r;
  scanf("%d", &n);
  for (i = 0; i < n; i++) {
    scanf("%d", &a);
    if (a > f) f = a;
  }
  scanf("%d", &n);
  for (i = 0; i < n; i++) {
    scanf("%d", &a);
    if (a > s) s = a;
  }
  scanf("%d", &n);
  for (i = 0; i < n; i++) {
    scanf("%d", &a);
    if (a < t) t = a;
  }
  scanf("%d%d", &a, &b);
  r = (double)f * sqrt((double)(s * b) / (t * a + s * b));
  printf("%.12lf", r);
  return 0;
}
