#include <bits/stdc++.h>
using namespace std;
const int MAXN = 5005;
int x[MAXN], y[MAXN], z[MAXN], A, B;
void Init() {
  int i;
  scanf("%d", &x[0]);
  for (i = 1; i <= x[0]; i++) {
    scanf("%d", &x[i]);
  }
  sort(x + 1, x + x[0] + 1);
  scanf("%d", &y[0]);
  for (i = 1; i <= y[0]; i++) {
    scanf("%d", &y[i]);
  }
  sort(y + 1, y + y[0] + 1);
  scanf("%d", &z[0]);
  for (i = 1; i <= z[0]; i++) {
    scanf("%d", &z[i]);
  }
  sort(z + 1, z + z[0] + 1);
  scanf("%d%d", &A, &B);
}
int main() {
  Init();
  int i = y[0], j = 1;
  double k = sqrt(double(B * y[y[0]]) / (A * z[1] + B * y[y[0]]));
  printf("%.8lf", k * x[x[0]]);
  return 0;
}
