#include <bits/stdc++.h>
using namespace std;
int m, n, k, A, B, x[10000 + 5], y[10000 + 5], z[10000 + 5];
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) {
    scanf("%d", &x[i]);
    x[1] = max(x[1], x[i]);
  }
  scanf("%d", &m);
  for (int i = 1; i <= m; ++i) {
    scanf("%d", &y[i]);
    y[1] = max(y[1], y[i]);
  }
  scanf("%d", &k);
  for (int i = 1; i <= k; ++i) {
    scanf("%d", &z[i]);
    z[1] = min(z[1], z[i]);
  }
  scanf("%d%d", &A, &B);
  printf("%.12lf\n", double(x[1]) / sqrt((double(A) * double(z[1])) /
                                             (double(B) * double(y[1])) +
                                         1.0));
  return 0;
}
